Direct Variation

Key Questions

• How do you determine if a function is a direct variation when given a table?

  Take note of the behavior of one variable and compare with the corresponding behavior of the other.

  If you increase the value of one variable, what happens to the value of the other variable? If it increases, you have a direct variation.
  If it decreases, you have a inverse variation

  seph · 3 · Oct 29 2014
• What is the constant of proportionality "k"?

  Direct Variation

  If `y` is directly proportional to `x`, then we can write

  `y=kx`,

  where `k` is the constant of proportionality.

  If you solve for `k`, we have

  `k=y/x`,

  which is the ratio of `y` to `x`.

  Hence, the constant of proportionality is the ratio between two quantities that are directly proportional.

  ---

  Inverse Variation

  If `y` is inversely proportional to `x`, then we can write

  `y=k/x`,

  where `k` is the constant of proportionality.

  If you solve for `k`, we have

  `k=xy`,

  which is the product of `x` and `y`.

  Hence, the constant of proportionality is the product of quantities that are inversely proportional.

  ---

  I hope that this was helpful.

  Wataru · 2 · Nov 11 2014
• How do you write direct variation equations?

  Direct Variation

  If `y` varies directly as `x`, then we can write

  `y=k cdot x`,

  where `k` is a constant of variation.

  ---

  I hope that this was helpful.

  Wataru · 1 · Nov 5 2014
• What is Direct Variation?

  When you have a direct variation, we say that as your variable changes, the resulting value changes in the same and proportional manner.

  A direct variation between `y` and `x` is typically denoted by

  `y = kx`

  where `k in RR`

  This means that as `x` goes larger, `y` also tends to get larger.
  The opposite is also true. As `x` goes smaller, `y` tend to get smaller.

  seph · 1 · Oct 29 2014

• What is Direct Variation?
• What does direct variation look like on a graph?
• What are examples of direct variation?
• How do you determine if a function is a direct variation when given a table?
• How do you write direct variation equations?
• What is the constant of proportionality "k"?
• Why is `y=2x-1` not a direct variation?
• How do you graph the direct variation equation `y=-\frac{1}{6}x`?
• What is the direct variation equation if y varies directly with x, and `y=7.5` when `x=2.5`?
• What is the direct variation equation if y varies directly with x, and `y=2` when `x=4`?
• What is the constant "k" in `y=-\frac{2}{3}x`?
• Why is `\frac{4}{x}=y` not a direct variation equation?
• If y varies directly as x and `x=15` when `y=3`, then how do you find y when `x=10`
• If y varies directly as x and `y=28` and `x=18`, how do you find y when `x = 9`?
• What direct equation relates x and y if y varies directly with x and `y=30` when `x=3`?
• How do you graph the direct variation equation `y=5/2x`?
• Is the equation `3x + 4y = 0` a direct variation and if it is, how do you find the constant of variation?
• How do you write a direct variation equation that passes through the point (5,-6)?
• If f(x) varies directly with x, and f(x) = 8 when x = 6, how do you write the direct linear variation equation?
• How do you find the direct variation equation of the graph through the points (0, 0) and (1, -2)?
• How do you write the direct variation equation of the graph through the points (0, 0) and (2, -2)?
• Is the equation `y = 5x` in direct variation and if so, what is the constant of variation?
• How do you write the direct variation equation if y varies directly as x, and y = 5 when x = -10?
• How do you write a direct variation equation if y=36 when x=9, and how do you find x when y=52?
• How do you write the direct linear variation equation for the relationship: y varies directly with x and y = 10 when x = 2?
• If f(x) varies directly with x, and f(x) = 12 when x = 8, how do you write the direct linear variation equation?
• How do you write a direct variation equation if y varies directly with x and y = 10 when x = 2?
• How do you find the constant of variation, and write an equation of direct variation that relates the two variables y= -10, for x=2?
• If -8 = y and -2 = x, how do you find x when y= 32?
• How do you find the direct variation equation of the graph through the points (0, 0) and (1, -10)?
• How do you write a direct variation equation that relates x to y and y = 4 when x = 2, then how do you find y when x = 16?
• How do you tell if a graph shows direct variation?
• How do you write a direct variation equation that relates x and y if y=-8 when x= 2, and how do you find y when x=32?
• How do you write an equation for a direct variation with a graph that passes through (6,2)?
• Given that y varies directly with x, how do you write a direct variation equation that relates x and y for x = 5, y = 10?
• Is `-8y = x + 2` a direct variation?
• How do you write a direct variation equation that relates x and y if y = -8 when x = -2 then how do you find x when y = 32?
• Is the equation `y=2x +5` a direct variation?
• Is this equation `-12x = 6y` a direct variation and if so, what is the constant?
• How do you find the direct variation equation which passes through (0, 0) and (4, 1)?
• How do you tell if an equation like `x+7y=0` or `2x+3y=1` is a direct variation?
• Is `3x-6y=0` a direct variation?
• Is `y = x^2` a direct variation equation?
• How do you find the variation constant and an equation of variation where y varies directly as x and y= 18 when x=2?
• What is the direct variation equation if f(x) varies directly with x and f(x) = –18 when x = 3?
• Is `x/y = 1/2` a direct variation equation?
• Is the equation `y = -15x` a direct variation, if so what is the constant of variation?
• How do you find a direct variation equation if y = 1/4 when x = 1/8, and how do you find x when y = 3/16?
• Is `3y - 7 = 10x` a direct variation equation?
• Is `y-x=4` a direct variation equation?
• Is `3y=1/3x` a direct variation, then if so, how do you find y when x=4?
• How do you determine whether the equation `7x + 2y = 0` represents a direct variation and if it does, how do you find the constant of variation?
• How do you figure out if y=1/2x is a direct variation?
• How do you find the direct variation equation if y = -16 when x = 4, and how find x when y = 20?
• How do you determine whether y varies directly with x and if so, how do you find the constant of variation k for `- 5y = 5x + 10`?
• What kind of variation is `xy=c`?
• What kind of variation is `x/y=c`?
• If the ordered pairs in this problem are for the same direct variation, how do you find the Missing value (2,3) and (6,y)?
• Is `y+8=-x` a direct variation?
• How do you write direct variation functions given f(2) = 8 and n = 4?
• Is `2y = 5x + 1` a direct variation and if so what is the constant?
• Is `8x + 9y = 10` a direct variation and if so what is the constant?
• Is `-x = 10y` a direct variation and if so what is the constant?
• Is `1/2x + 1/3y = 0` a direct variation and if so what is the constant?
• Is `-12x = 6y` a direct variation and if so what is the constant?
• Is `x=-7` a direct variation and if so what is the constant?
• Is `3x-3y=0` a direct variation and if so what is the constant?
• Is `x+y=6` a direct variation and if it is, how do you find the constant?
• Is `y=12x` a direct variation and if it is, how do you find the constant?
• Is `y-6x=0` a direct variation and if it is, how do you find the constant?
• Is `y=8x` a direct variation and if it is, how do you find the constant?
• Is `y=2x+1` a direct variation and if it is, how do you find the constant?
• Is `3x+y=6` a direct variation and if it is, how do you find the constant?
• Is `5y = -4x` a direct variation and if it is, how do you find the constant?
• The variables x and y vary directly, how do you write an equation that relates x and y when given x = -18, y = -2, and then how do you find x when y=4?
• Is `y = 2x + 5` a direct variation and if so, how do you find the constant?
• Is `9x + 5y = 0` a direct variation and if so, how do you find the constant?
• Is `-4x + y = 0` a direct variation and if so, how do you find the constant?
• Is `y/6 = x` a direct variation and if so, how do you find the constant?
• The ordered pair (1.5, 6) is a solution of direct variation, how do you write the equation of direct variation? Represents inverse variation. Represents direct variation. Represents neither.?
• The ordered pair (7, 21) is a solution of direct variation, how do you write the equation of direct variation?
• Is `y=5/2x` a direct variation and if so, how do you find the constant?
• Is `3x=y` a direct variation and if so, how do you find the constant?
• Is the equation y=3/x represents a direct variation?
• Is `y= -8x` a direct variation?
• Is `y= -2/x` a direct variation?
• Is `y= x^3` a direct variation?
• If y varies inversely as x, how do you find the constant of variation if y=14 when x=8?
• In the direct variation model, y=.5x, if y=10, how do you give the value of x?
• If y varies directly as x and y = 198 when x = 22, how do you find y when x = 182?
• If y varies directly as x and if x = -6when y = 2 how do you find x when y = -9, -8,-6, -5, -4, -3?
• Is `y = 3x/2` a direct variation?
• If y is directly proportional to the square of x, when x=4 y = 25, how do you find an expression for y in terms of x?
• A group of friends rent a house at the beach for spring break. If nine of them share the house, it costs $150 each. Is the cost to each person directly or inversely proportional to the number of people sharing the house?
• What is an example of directly proportional?
• If y is directly proportional to x^2 and y = 36, when x=3 work out a formula connecting y & x ?
• Y is directly proportional to x and inversely proportional to the square of z and y = 40 when x = 80 and z = 4, how do you find y when x = 7 and z = 16?
• Is the relationship between temperature and volume directly or inversely proportional?
• If "y" is inversely proportional to "x" and "y"=15 when "x"=5, What is the value of "y" when "x"=25?
• If p is directly proportional to q, and p =9 when q = 7.5, how do you find q when p =24?
• If the equation y=5/7x describes a proportional relationship between x and y, what is the constant of proportionality?
• If y varies jointly with x and z, what is the constant of proportionality when y = 30, x = 4, and z = 5?
• How do you determine the constant of proportionality if r varies directly as p and r = 3 when p = 15?
• Cost varies directly as time and the cost is $8 when the time is 2 hours, what is the constant of proportionality?
• Given y inversely proportional to x and x = 3 for y = 6, what is x if y = 9?
• Given y inversely proportional to x and x = 3 for y = 4, what is x if y = 12?
• What is the constant of proportionality for the equation y = (1/5)x?
• How do you name the Constant of Variation in the equation, `y = 3x`?
• How do you name the Constant of Variation in the equation, `3x + 5y = 0`?
• How do you name the Constant of Variation in the equation, `y=4x`?
• How do you name the Constant of Variation in the equation, `y=x`?
• How do you name the Constant of Variation in the equation, `y=-x`?
• How do you name the Constant of Variation in the equation, `y=-2x`?
• How do you name the Constant of Variation in the equation, `5x-3y=0`?
• How do you name the Constant of Variation for a line passing through (0,0) and (4,-3)?
• How do you find the variation constant and an equation of variation where y varies directly as x and y=12 when x=2?
• How do you find the variation constant and an equation of variation where y varies directly as x and y=-2 when x=14?
• How do you find the variation constant and an equation of variation where y varies directly as x and y = 1 when x = 15?
• How do you determine the constant of variation for the direct variation given (0, 0), (3, 12), (9, 36)?
• How do you determine the constant of variation for the direct variation given `-5y=2x`?
• How do you determine the constant of variation for the direct variation given `-4y=8x+16`?
• How do you find the variation constant and an equation of variation where y varies directly as x and y=4.5 when x=3?
• How do you find the variation constant and an equation of variation where y varies directly as x and y = 2.52 when x = 8.4?
• How do you determine the constant of variation for the direct variation given `Y=-3/2x`?
• How do you determine the constant of variation for the direct variation given `-6y=-3x`?
• How do you determine the constant of variation for the direct variation given `2x - y=0`?
• How do you determine the constant of variation for the direct variation given `y/x = 4/3`?
• How do you determine the constant of variation for the direct variation given `y = 8x`?
• How do you determine the constant of variation for the direct variation given by (1,8) (2,4) (4,2) (8,1)?
• How do you determine the constant of variation for the direct variation given by `2x=4y`?
• How do you determine the constant of variation for the direct variation given by `y=40x`?
• How do you determine the constant of variation for the direct variation given by `y=50x`?
• How do you determine the constant of variation for the direct variation given by `4x=-y`?
• What is the direct variation when y = 10 and x = 5?
• Is the equation `y=3/x` a direct variation, if so what is the constant of variation?
• Is the equation `y=3` a direct variation, if so what is the constant of variation?
• Is the equation `y=3-x` a direct variation, if so what is the constant of variation?
• If y varies directly with x and y = 1 when x = 15, how do you find x when y = 8?
• If y varies directly with x and y = -4.5 when x = 13.5, how do you find x when y = 24?
• If y varies directly with x and y = -4 when x = 12.5, how do you find y when x = 24?
• The circumference of a circle varies directly with the diameter. If the circumference is 18.85 inches for a circle with a diameter of 6 inches, what is the circumference of a circle with a diameter of 11 inches?
• The weight of an object on earth varies directly with its weight on the moon. If a baby weighing 24 pounds on the earth only weighs 3.84 pounds on the moon, how much does a 194-pound man weigh on the moon?
• Each pair of values is from direct variation, how do you find the missing value for (3,7) (8,y)?
• How do you know if an equation `y=0.5x` is a direct variation And if it is how do you find the constant of the variation?
• How do you know if an equation `6x-5y=4` is a direct variation And if it is how do you find the constant of the variation?
• How do you tell whether the equation x + 2y = 4 represents a direct variation. If so identify the constant?
• Assuming that y varies directly x, if y = 4 when x = 2, how do you find y when x = 16?
• Assuming that y varies directly x, if y = 1/4 when x = 1/8, find x when y = 3/16?
• How do you write the direct variation equation if y= 45 when x=15, find x when y=15?
• How do you write the direct variation equation if y=-4 when x=2, find y when x=-6?
• How do you write the direct variation equation if y=-9 when x= 3, find y when x=-5?
• How do you write the direct variation equation if y=4 when x=16, find y when x=6?
• How do you write the direct variation equation if y=12 when x=18, find x when y=-16?
• How do you write the direct variation equation if y = 8 when x = 24?
• How do you write the direct variation equation if f(x) = –18 when x = 3?
• Is y=3x a direct variation and if so, what is the constant?
• Is y=2x-9 a direct variation and if so, what is the constant?
• Is 2x+3y=0 a direct variation and if so, what is the constant?
• Is 3y=9x a direct variation and if so, what is the constant?
• Is y=2x +5 a direct variation and if so, what is the constant?
• Is y=5 a direct variation and if so, what is the constant?
• Is y=5-x a direct variation and if so, what is the constant?
• How do you write the direct variation equation if y=42 as x=6, find y for the x-value 3?
• If y varies directly as x and y = 10 when x = 2, what is y when x = 3?
• How do you write direct variation equations given y = 32 when x = 8?
• If y varies directly as x and y = 270 when x = 15, how do you find y when x = 19?
• If y varies inversely as v and x = 63 when v = 6, how do you find x when v = 54?
• Is `y = x` direct variation and if so what is the constant?
• How do you find the direct variation equation of the graph through the points (0, 0) and (1, -2)?
• Y varies directly with x and y = 12 when x = 4, how do you write the direct variation equation?
• How do you tell wether the equation `y = 8x` represents direct variation and if so, how do you identify the constant of variation?
• How do you tell wether the equation `y = 2x + 1` represents direct variation and if so, how do you identify the constant of variation?
• How do you tell wether the equation `3x + y = 6` represents direct variation and if so, how do you identify the constant of variation?
• Given that y varies directly with x, and x = 24, y = 3, how do you write a direct variation equation that relates x and y?
• Given that y varies directly with x, and x = -16, y = -4, how do you write a direct variation equation that relates x and y?
• Given that y varies directly with x, and x = 28, y = -4, how do you write a direct variation equation that relates x and y?
• Given that y varies directly with x, and x = 5, y = -30, how do you write a direct variation equation that relates x and y?
• Given that y varies directly with x, and x = 1/6, y = 1, how do you write a direct variation equation that relates x and y?
• Given that y varies directly with x, and x = 8, y = -3, how do you write a direct variation equation that relates x and y?
• Given that y varies directly with x, and x = 6, y = 102, how do you write a direct variation equation that relates x and y?
• Given that y varies directly with x, and x = 15, y = 9, how do you write a direct variation equation that relates x and y?
• What is the direct variation equation that goes through point (2,5)?
• Is `xy=4` a direct variation equation and if so, what is the constant of variation?
• Is `x=y/4` a direct variation equation and if so, what is the constant of variation?
• Is `4x=y` a direct variation equation and if so, what is the constant of variation?
• Is `y=0.5x` a direct variation equation and if so, what is the constant of variation?
• Is `6x-5y=4` a direct variation equation and if so, what is the constant of variation?
• Is `3x + 4y = 0` a direct variation equation and if so, what is the constant of variation?
• Is `y=5x` a direct variation equation and if so, what is the constant of variation?
• Is `2x=4y` a direct variation equation and if so, what is the constant of variation?
• Is `y=8` a direct variation equation and if so, what is the constant of variation?
• Is `y=-10x` a direct variation equation and if so, what is the constant of variation?
• If y varies directly with x, and y = 28 when x = 7, how do you write the direct linear variation equation?
• If y varies directly with x, and y = 0.7 when x = 0.4, how do you write the direct linear variation equation?
• If y varies directly with x, and y = 0.8 when x = 0.5, how do you write the direct linear variation equation?
• Is `2x - 5y = 0` a direct variation equation and if so, what is the constant of variation?
• Is `3y + 2= 2x` a direct variation equation and if so, what is the constant of variation?
• Is `-7x=-56y` a direct variation equation and if so, what is the constant of variation?
• If y varies directly with x, and y = -15 when x = -5, how do you write the direct linear variation equation and then use the equation to find x when y =12?
• Is `-3x+2y=0` a direct variation equation and if so, what is the constant of variation?
• Is `2y=3x` a direct variation equation and if so, what is the constant of variation?
• Is `x+y=6` a direct variation equation and if so, what is the constant of variation?
• Is `3x = y` a direct variation equation and if so, what is the constant of variation?
• Is `y =4.2/x` a direct variation equation and if so, what is the constant of variation?
• Is `y/x = 6` a direct variation equation and if so, what is the constant of variation?
• Is `y= 0.5x+9` a direct variation equation and if so, what is the constant of variation?
• If y varies directly with x, and y = 6 when x = 20, how do you write the direct linear variation equation?
• If y varies directly with x, and y = 5 when x = 8, how do you write the direct linear variation equation and what is the value of x when y = 15?
• The number of miles Abigail’s boat travels, m, varies directly with the amount of time Abigail spends boating, t. If she spends 2 h in her boat, she travels 19 mi. How do you model this with a direct linear variation?
• Is `y=12x` a direct variation equation and if so, what is the constant of variation?
• Is `y-6x=0` a direct variation equation and if so, what is the constant of variation?
• Is `5x = -3y` a direct variation equation and if so, what is the constant of variation?
• The cost of pens varies directly with the number of pens. One pen costs $2.00. How do you find k in the equation for the cost of pens, use C=kp, and how do you find the total cost of 12 pens?
• If y varies directly with x, and y = 50 and x = 4, how do you write the direct linear variation equation and what is the constant?
• If y varies directly with x, and y = 32 when x = 8, how do you write the direct linear variation equation and what is the constant?
• If y varies directly with x, and y = 45 when x = 5, how do you write the direct linear variation equation and what is the constant?
• Is `y=3/4x-7` a direct variation equation and if so, what is the constant of variation?
• If y varies directly with x, and if y =45 when x=15, how do you find x when y = 15?
• Is `1 - y = 2x` a direct variation equation and if so, what is the constant of variation?
• Is `x-3y=0` a direct variation equation and if so, what is the constant of variation?
• Is `y=7-3x` a direct variation equation and if so, what is the constant of variation?
• Is `3x-7y=1` a direct variation equation and if so, what is the constant of variation?
• Is `3x-7y=0` a direct variation equation and if so, what is the constant of variation?
• Is `3y=7x-1` a direct variation equation and if so, what is the constant of variation?
• The ordered pair (2, 10), is a solution of a direct variation, how do you write the equation of direct variation, then graph your equation and show that the slope of the line is equal to the constant of variation?
• Is this an inverse variation, or an direct variation: It takes 5 hours for 2 cooks to prepare food for a wedding rehearsal. How long will it take 8 cooks to prepare the dinner?
• If y varies directly with x, and if -8 = y and -2 = x, how do you find x when y= 32?
• Is `7x+4y=2` a direct variation equation and if so, what is the constant of variation?
• Is `y=2x-9` a direct variation equation and if so, what is the constant of variation?
• Is `2x+3y=0` a direct variation equation and if so, what is the constant of variation?
• Is `3y=9x` a direct variation equation and if so, what is the constant of variation?
• Is `4x = -6y` a direct variation equation and if so, what is the constant of variation?
• Is `3x + 5y =0` a direct variation equation and if so, what is the constant of variation?
• Is `y=3.2x` a direct variation equation and if so, what is the constant of variation?
• Is `x/y = 1/2` a direct variation equation and if so, what is the constant of variation?
• Is `5y=-4x` a direct variation equation and if so, what is the constant of variation?
• If f(x) varies directly with x and f(x) = 24 when x = –4, then what is f(x) when x = 12?
• If y varies directly with x, and if y = 12 when x = 3, how do you write the direct variation equation?
• The ordered pairs (3,4) and (9,y) are for the same direct variation, how do you find each missing value?
• The ordered pairs (-1,2) and (4,y) are for the same direct variation, how do you find each missing value?
• Is `y = -x` a direct variation equation and if so what is the constant?
• Is `4x - 3y = 0` a direct variation equation and if so what is the constant?
• Is `2x + y = 4` a direct variation equation and if so what is the constant?
• If y varies directly with x, and y=36 when x=9, how do you find x when y=52?
• Is `8x +2y =0` a direct variation equation and if so what is the constant?
• Is `y=217x` a direct variation equation and if so what is the constant?
• What is the constant of variation, k, of the direct variation, y = kx, through (–3, 2)?
• The slope of the graph of a direct variation function is 4. What is the equation of the function?
• Is `3x-6y=0` a direct variation equation and if so what is the constant?
• Is `f(x)=13x` a direct variation equation and if so what is the constant?
• Is `8y=x` a direct variation equation and if so what is the constant?
• Is `y/x = 8` a direct variation equation and if so what is the constant?
• How do you draw the graph of direct variation that includes the point (1,6) and write the equation of the line?
• Is `y=2x` a direct variation equation and if so what is the constant?
• What is the constant of variation, k, of the direct variation, y = kx, through (5, 8)?
• If y varies directly with x, and x = -6 when y = 2 and how do you find x when y = -9?
• If y varies directly with x, and If y = 8 when x = 4, how do you find y when x = 5?
• If y varies directly with x, and If y = -36 when x = 6, how do you find x when y = 42?
• If y varies directly with x, and If y = -16 when x = 4, how do you find x when y = 20?
• If y varies directly with x, and If y = -18 when x = 6, how do you find x when y = 6?
• If y varies directly with x, and If y = 4 when x = 12, how do you find y when x = -24?
• If y varies directly with x, and If y = 12 when x = 15, how do you find x when y = 21?
• If y varies directly with x, and If y = 2.5 when x = 0.5, how do you find y when x = 20?
• Is `-x+4y=-2` a direct variation equation and if so what is the constant?
• Is `d=4t` a direct variation equation and if so what is the constant?
• Is `y=2/3x` a direct variation equation and if so what is the constant?
• Is `3x-y=0` a direct variation equation and if so what is the constant?
• Is `-x+2y=0` a direct variation equation and if so what is the constant?
• Is `4x+2y=7` a direct variation equation and if so what is the constant?
• Is `y/6 = x` a direct variation equation and if so what is the constant?
• If y varies directly with x, and if y = 2 when x = 6, how do you find the direct variation equation?
• If y varies directly with x, and if y = 2/3 when x = 1/4, how do you find the direct variation equation?
• If y varies directly with x, and if y=2 when x=.25, how do you find the direct variation equation?
• Is `x- 3y = 6` a direct variation equation and if so what is the constant?
• The equation -4x + y = 0 relates the number of pages in a photo album y to the number of pictures in the album x. How do you tell whether the relationship is a direct variation?
• The distance that you travel at a constant speed varies directly with the time spent traveling. It takes you 2 h to travel 100 mi. Write an equation for the relationship between time and distance. How far would you travel in 3.5 h?
• How do you write a direct variation equation that relates the variables then graph if the total cost C of gasoline is $1.80 times the number of gallons G?
• How do you write a direct variation equation that relates the variables then graph if the number of delivered toys T is 3 times the total number of crates c?
• Is `y=3/5x` a direct variation equation and if so what is the constant?
• Is `y=-2x` a direct variation equation and if so what is the constant?
• Is `y = 2/5x` a direct variation equation and if so what is the constant?
• Is `y=-8x` a direct variation equation and if so what is the constant?
• Is `5y=-4x` a direct variation equation and if so what is the constant?
• Is `3y-7=10x` a direct variation equation and if so what is the constant?
• Is `2y-5x=0` a direct variation equation and if so what is the constant?
• Is `-3x=2y=0` a direct variation equation and if so what is the constant?
• Is `y/x = 4/3` a direct variation equation and if so what is the constant?
• If y varies directly with x, and if x = 7.5 when y = 10, how do you find x when y = 4?
• In a circle, the circumference and diameter vary directly. How do you find the diameter of a circle with a circumference of 154 if you know that in a second circle the diameter is 14 when the circumference is 44?
• If three men working at the same hourly rate are paid a total of $52.08 for a day's work, how much should be paid to five men at the same hourly rate?
• If the cost of a telephone conversation varies directly as the length of the time of conversation, and if the cost of six minutes is $0.90, what would be the cost for a nine-minute call?
• The volume (v) of a sphere varies directly as the cube of its diameter (d). How do you write this statement in algebraic language, using an equation with the variables c, v, and d.?
• Is `f(x)=x+2` a direct variation equation and if so what is the constant?
• Is `f(x)=2` a direct variation equation and if so what is the constant?
• If y varies directly with x, and if y=5 when x=-0.1, how do you find the direct variation equation?
• If y varies directly with x, and if y = 14 when x = -14, how do you find the direct variation equation?
• If y varies directly with x, and if y = 10 when x = 2, how do you find the direct variation equation?
• Is `5x-6y=0` a direct variation equation and if so what is the constant?
• Is `y=x-3` a direct variation equation and if so what is the constant?
• How do you write the direct variation of (3, 1/2)?
• How do you write the equation of a direct variation that includes the point (-6,1)?
• Is `y = x +2` a direct variation equation and if so what is the constant?
• Is `y = -4x` a direct variation equation and if so what is the constant?
• Is `y = -x - 1` a direct variation equation and if so what is the constant?
• Is `y = 2` a direct variation equation and if so what is the constant?
• Is `y = 1/2x` a direct variation equation and if so what is the constant?
• If y varies directly with x, and If y = 14 when x = 5, how do you find x when y = 28?
• If y varies directly with x, how do you find y when x = 5 if y = -6 when x = 2?
• If y varies directly with x, if x =9 when y = 18, how do you find x when y =24?
• If y varies directly with x, if y = 36 when x = -6, how do you find x when y = 54?
• If y varies directly with x, how do you find y when x = 3 if y = -3 when x =6?
• If y varies directly with x, if y = 8 as x = -4 how do you find the direct variation equation?
• If y varies directly with x, if y=8 when x=3 how do you find the direct variation equation?
• If y varies directly with x, if y=4 when x=16, how do you find y when x=6?
• If y varies directly with x, if y=12 when x=18, how do you find x when y=-16?
• If y varies directly with x, if y=-9 when x= 3, how do you find y when x=-5?
• How do you proof that for `a,b,cinRR`, `a/b=b/c=c/a<=>a=b=c`?
• `a+3/(4b)=2` and `b+3/(4a)=6`. How do you find `b/a`?
• If y varies directly as x, and y = 30 when x = 4, how do you find the constant of proportionality?
• The amount of material needed to cover a ball varies directly with the square of the radius. It takes about 221.63 cm2 of material to cover a ball with a radius of 4.2 cm. What is the radius of a ball that needs 352.92 cm2 of material to cover it?
• Question #a03fe
• Question #2539b
• If the surface area of a sphere and a cube are equal then how do you show that their volumes are in the ratio `sqrt(7) : sqrt(5)` ?
• The volume of an enclosed gas (at a constant pressure) varies directly as the absolute temperature. If the pressure of a 3.46-L sample of neon gas at 302°K is 0.926 atm, what would the volume be at a temperature of 338°K if the pressure does not change?
• If y varies directly as the square of x. When x = 2, y = 20, how do you find y when x = 4?
• If y varies jointly with p and q. When p = 3 and q = 3, y = 90, how do you find y when p = 7 and q = 5?
• Suppose y varies directly as x and y = 27 when x=3, how do you find x when y = 45?
• If `y` varies directly with `x` and `y=10` when `k=10`, what is the value of `x`?
• If volume of a pyramid is given by `V=1/3Ah`, find volume of pyramid, whose base area is `15` and height is `7`?
• The variables x and y vary directly. When x = 12, y = 9. How do you write an equation that relates the variables?
• Is `Y=5x` a direct variation?
• The area formula for a parallelogram with area 36 is bh = 36. Does the formula represent a direct or an inverse variation?
• The time t required to drive a certain distance varies inversely with the speed r. If it takes 2 hours to drive the distance at 45 miles per hour, how long will it take to drive the same distance at 30 miles per hour?
• A cruise ship is traveling at a rate of 20 miles per hour. How do you use a direct variation formula to calculate the number of miles traveled in 7 hours?
• How do you write an equation of the direct variation that includes the given point (5, 1)?
• Michael has a water pump that will pump water at the rate of 5 gallons per minute. How do you use a direct variation formula to determine how many minutes it will take the pump to remove 60 gallons of water?
• How do you find an equation of variation where y varies directly as x and y = 0.8 when x = 0.4?
• How do you find an equation of variation where y varies directly as x and y = 2 when x = 10, find y when x = -25?
• Is `y=3x` a direct variation and if so what is the constant?
• If x=0.5 when y=6.24 and y varies inversely with x, which shows y when x=2.6?
• If x = 27 when y = 70 and x varies directly with y, then how do you find x when y = 190?
• How do you find the value of y when x=0.5. for y=4 when x=0.5?
• For a direct variation if y=2 when x= -4, how do you find x when y=20?
• How do you write an equation in the form f(x) = kx^n for the direct variation functions given f(2) = 8 and n = 4?
• How do you write an equation in the form f(x) = kx^n for the direct variation functions given f(0.3) = 45 and n = 2?
• For the direct variation y = 3 when x = -2, how do you find the constant of variation and find the value of y when x = 3?
• For the direct variation y = (3/4) when x = (1/8), how do you find the constant of variation and find the value of y when x = 3?
• For the direct variation y = (-3/8) when x = (-2/3), how do you find the constant of variation and find the value of y when x = 3?
• Tommy averages one hit for each five times at bat. How do you use a direct variation formula to determine how many hits would be expected from Tommy after 20 times at bat?
• Is `x+7y=0` a direct variation?
• If y varies directly with x and y=21 when x=7, how do you find y when x=-1.66?
• Is `1- y = 2x` a direct variation?
• How do you find an equation of variation where y varies directly as x and y = 10 when x = 5, find y when x is 4?
• How do you write the direct variation of (2, 10)?
• How do you write the direct variation of (-3, 9)?
• P varies directly with Q and inversely with R. P=9, when Q=3 and R=4. How do you find Q when P=1 and R=1/2?
• Does the equation `-x + 4y = -2` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y/6 = x` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y=8` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y=5x+2` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y=-10x` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y=x^3` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y = x/2` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y = 2x` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y = 2/x` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y = x^2` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y=3/5x` represent a direct variation and if so, identify the constant of variation?
• Does the equation `2x - 5y = 0` represent a direct variation and if so, identify the constant of variation?
• Does the equation `3y + 2= 2x` represent a direct variation and if so, identify the constant of variation?
• If y varies directly as x, how do you find the direct variation equation for the situation. y = 0.5 when x = 2?
• Does the equation `3x - 6y = 0` represent a direct variation and if so, identify the constant of variation?
• Variable y varies directly with variable x, and y = 9 when x = 5. What is the constant of variation in decimal form?
• Suppose y is inversely proportional to x. If y = 6 when x = 4, how do you find the constant of proportionality and write the formula for y as a function of x and use your formula to find x when y = 8?
• How do you write an equation for the direct variation that includes the given point: (7, -2)?
• If w is jointly proportional to u and v, and w=2 when u=4 and v=6, what is w when u=3 and v=8?
• Suppose that r varies directly as p and inversely as q², and that r=27 when p=3 and q=2. How do you find r when p=2 and q=3?
• Suppose x varies jointly as y and z. If x=50 when y=2 and z=4, how do you find x when y=6 and z=10?
• Does the equation `7x+4y=2` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y = 4x` represent a direct variation and if so, identify the constant of variation?
• How do you find the constant of variation for a direct variation that includes the given values (2,4)?
• Y varies directly with x, y=65 when x=5. How do you find y when x=12?
• Does the equation `y=5/2x` represent a direct variation and if so, identify the constant of variation?
• Does the equation `3x+5y=0` represent a direct variation and if so, identify the constant of variation?
• How do you find the equation given that y varies directly with x, write the linear function relating the two variables and when x=3 y=6?
• Does the equation `f(x)= 40x` represent a direct variation and if so, identify the constant of variation?
• If f(x) varies directly with x, and f(x) = 48 when x = 8, how do you find the value of f(x) when x = 2?
• The number of calories burned, C, varies directly with the time spent exercising, t. When James runs for 2 hours, he burns 800 calories. How do you write an equation that shows this direct linear variation?
• How do you find the constant of variation, and write an equation of direct variation: y=5 when x=-0.1?
• Does the equation `8x +2y =0` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y = 3x` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y = 3` represent a direct variation and if so, identify the constant of variation?
• Does the equation `y = 3.14 x` represent a direct variation and if so, identify the constant of variation?
• If x varies directly as y and x is 5 when y is 15, how do you find the constant of variation?
• Does the equation `12x = 36y` represent a direct variation and if so, identify the constant of variation?
• Y varies directly as X. If y=18 when x=6, how do you find the formula, then find y when x is 3?
• Variable A varies directly with P and Q. If A=42 when P=8 and Q=9, how do you find A when P=44 and Q=7?
• Does the equation `y = 2x + 1` represent a direct variation and if so, identify the constant of variation?
• Does the equation `3x + y = 6` represent a direct variation and if so, identify the constant of variation?
• Does the equation `2x=4y` represent a direct variation and if so, identify the constant of variation?
• How do you write an equation of the direct variation that includes the point (–5, 17)?
• M varies directly with n; m
  = 144 when n =
  8, how do you write the direct variation equation?
• For a direct variation, if y=-4.8 when x=-1.6, how do you find x when y=-24?
• Does the equation `y = 4x + 9` represent a direct variation and if so, identify the constant of variation?
• Does the equation `2y = - 8x` represent a direct variation and if so, identify the constant of variation?
• The value of y varies directly with x, and y = 6 when x = 18, how do you find y when x = 12?
• A cheetah’s distance traveled varies directly with the amount of time it runs. The cheetah travels 90 m in 2.5 s.? How many meters will it travel in 4 s?
• The ordered pairs (2,y) and (10,15) are the same direct variation, how do you find each missing value?
• The ordered pairs (3,y) and (1/5,6) are the same direct variation, how do you find each missing value?
• Suppose you earn $127 for working 20 hours, write a direct variation equation relating your earnings to the number of hours worked and calculate how much you would earn for working 35 hours?
• Y varies directly as X, how do you find the constant of variation given Y= -6/7 when X= -18/35?
• A variable `y` varies directly with the square of `x`. If `x=3` when `y=6`, what is the constant of proportionality, `k`?
• Suppose r varies directly with t and that r = 25 when t=25 . What is the value of r when t = 7?
• If y is directly proportional to x and y=5 when x=2, what is the value of y when x=16?
• Let V and W be the subspace of `RR^2` spanned by (1,1) and (1,2),respectively. Find vectors `v ∈ V and w ∈ W` so `v + w = (2,−1)`?
• Question #ac2d1
• Is this equation a function?Why/Why not?
• The variables x=2 and y=7 varies directly. How do you write an equation that relates the variables and find y when x=8?
• The variables x=-6 and y=15 varies directly. How do you write an equation that relates the variables and find y when x=8?
• The variables x=-3 and y=9 varies directly. How do you write an equation that relates the variables and find y when x=8?
• The variables x=24 and y=4 varies directly. How do you write an equation that relates the variables and find y when x=8?
• The variables x=1 and y=1/2 varies directly. How do you write an equation that relates the variables and find y when x=8?
• The variables x=0.8 and y=1.6 varies directly. How do you write an equation that relates the variables and find y when x=8?
• The variables x=6 and y=3 varies directly. How do you write an equation that relates the variables and find x when y=-5?
• The variables x=9 and y=15 varies directly. How do you write an equation that relates the variables and find x when y=-5?
• The variables x=-5 and y=-1 varies directly. How do you write an equation that relates the variables and find x when y=-5?
• The variables x=100 and y=2 varies directly. How do you write an equation that relates the variables and find x when y=-5?
• The variables x=5/2 and y=5/4 varies directly. How do you write an equation that relates the variables and find x when y=-5?
• The variables x=-0.3 and y=2.2 varies directly. How do you write an equation that relates the variables and find x when y=-5?
• Question #6a0ca
• Suppose that z = x + yi, where x and y are real numbers. If `(iz-1)/(z-i)` is a real number, show that when (x, y) do not equal (0, 1), `x^2` + `y^2` = 1?
• When making pancakes, the amount pancake mix varies directly with the number of pancakes made. If 2 cups of min Produces 13 pancakes, how many pancakes would be produce with 12 cups of pancake mix?
• The value of y varies directly with x. Which function represents the relationship between x and y if y=20/3 when x=30?
• X varies directly as y, and x= 153 when y=9. How do you find x when y=13?
• If x varies inversely as y and directly as t, and x =12 when t =10 and y =25, how do you find y when x is 6 and t= 3?
• Given y varies directly with x, write the equation of the line when x=3 and y=-12?
• Your weight on Mars varies directly with your weight on Earth. A person weighing 125 lbs on Earth weights 47.25 lbs on Mars, since Mars has less gravity. If you weigh 155 lbs on Earth, how much will you weigh on Mars?
• How do you find variation constant and an equation of variation where y varies directly as x and y=56 when x=8?
• Y is directly related to X and Y is 81 when X is 27. What is the constant of variation?
• Question #5deb8
• How do you find the constant of proportionality from the equation `y=7.5x`?
• How do you find the constant of proportionality from the equation `y=4x`?
• The volume of a cylinder of fixed height varies in direct proportion to the square of the base radius. How do you find the change in volume when the base radius is increased by 18%?
• Question #3c845
• Question #ffc8d
• How can we write the relation between miles and kilometers in the form of an equation?
• How do you determine whether the equation `-12x=6y` represents direct variation. If it does, how do you find the constant of variation?
• Is the equation `y=x-2` a direct variation? If it is, how do you find the constant of variation?
• X and y vary directly. When x is 24, y is 8. What is x when y is 9?
• X and y vary directly. When x is 5, y is -30. What is y when x is -3?
• Suppose that y varies jointly with w and x and inversely with z and y=360 when w=8, x=25 and z=5. How do you write the equation that models the relationship. Then find y when w=4, x=4 and z=3?
• How do you find the value of y for a given value of x, if y varies directly with x. If y=166 when x=83, what is y when x=237?
• Question #d787f
• The quantity y varies directly with the square of x and inversely with z. When x is 9 and z is 27, y is 6. What is the constant of variation?
• The amount of time p people to paint d doors varies directly with the number of doors and inversely with the number of people. Four people can paint 10 doors in 2 hours How many people will take to paint 25 doors in 5 hours?
• Question #92b82
• What is the constant of variation for 3x=4y?
• Does 3x=4y represent a direct variation?
• Let S={v1=(2,2,3), v2=(-1,-2,1), v3=(0,1,0)}. Find a condition on a,b, and c so that v=(a,b,c) is a linear combination of v1,v2 and v3?
• Is this equation a direct variation 2y-x=2x?
• The function f(x) varies directly with x and f(x)= 90 when x=30. What is f(x) when x=6?
• Question #8016b
• How do you find the value of y for a given value of x if y is 3.3 when x is 1.65, what is y when x is 4.85?
• Suppose y varies directly with x and y=24 when x=8. What is the value of when x=10?
• For the equation `-4y=8x`, what is the constant of variation?
• How do you determine whether the equation represents a direct variation. If it does, find the constant of variation 2y=5x+1?
• Is the equation `6x^2+3y=0` an example of direct variation?
• Question #58049
• If y varies directly as x, and y=9 when x=4, how do you find y when x=16?
• Question #88697
• Question #267da
• Question #fea28
• Question #93634
• What number divided by 6 gives 16?
• Question #1182f
• Question #f65fd
• Question #91fad
• Z varies directly as the square of w, and z = 14 when w = 4. Find z when w = 8?
• Question #1efbd
• M varies directly as the square of x. If m = 200 when x = 20, find m when x is 32?
• Question #8333d
• Y varies jointly as the cube of x and the square root of w, and Y = 128 when x = 2 and w = 16. Find Y when x = 1/2 and w = 64? P.S. Thank you for helping me for this problem.
• Question #e8f46
• Question #4d848
• Question #2c599
• If `y=166` when `x=83`, what is `y` when `x=23`?
• Nyoko is having a pizza party. If two large pizzas serve 9 people, what scale factor could she use to determine how many pizzas she would need, in order to serve 27 guests at the party?
• Question #80ebe
• Question #3d3d7