How do you graph y=4x?

3 Answers
Apr 13, 2016

graph{y=4x [-10, 10, -5, 5]}

Explanation:

Graph y=4x
First, determine your slope and y-intercept.
(Your equation is in slope-intercept form)
Slope-intercept Form: y=mx+b
m is the slope
b is the y-intercept

In your equation, the slope is 4 and the y-intercept is 0.

Because your y-intercept is 0, place your first point at (0,0). Your second point should be at (1,4) because the graph rises 4 units for every 1 unit is runs.

graph{y=4x [-10, 10, -5, 5]}

Apr 13, 2016

Take for x any two numbers. Let the x be 1 and 2.
So, according to the equation the results for the y would be as follows:
y=4*1=4 so this is (x,y)=(1,4), and
y=4*2=8 => (2,8)
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Apr 13, 2016

underline("Full explanation")" " given about principle and method for this question.

Explanation:

The number in front of the x is the gradient (slope). This number represents the amount of up or down for a given amount of along. This is determined reading from left to right.

The value of 4 is really 4/1. This means that for 1 along you go up 4.

If the number in front of the x (coefficient) is positive the 'slope' goes up. If the coefficient is negative it means the 'slope' is down.

For this question; substitute any value you chose into x, multiply it by 4 and you have your value for y
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Let x=0 -> y=4(0)

At x=0 " we find that "y=0

So this can be our first point on the graph.

color(blue)("Point"_1 -> (x_1,y_1)->(0,0))
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Choosing a number at random: I chose 2

Let x=2 ->y=4(2)

At x=2 " we find that "y=8

So this can be our second point on the graph.

color(blue)("Pont"_2->(x_2,y_2)->(2,8))
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Note that gradient ->("change in y axis")/("change in x axis") -> (y_2 -y_1)/(x_2-x_1)

=(8-0)/(2-0)" " =" "8/2" "=" "4/1" " reading left to right.
'~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Mark your two points on the graph paper. Draw a line through them extending it to the edges of the axis.

color(red)("Label your axis "-> " extra marks")
color(red)("Label your graph" ->" extra marks")

The label could read something like:

"graph of y=4x"

Tony B