How do you graph f(x)= 1/4x + 8 by plotting points?

2 Answers
Nov 25, 2017

See explanation.

Explanation:

To pliot a linear function you only need 2 points. So the easiest way to plot a function is to substitute 2 integers to calculate the points.

f(0)=1/4*0+8=8

Since there is a denominator 4 it will be easier to substitute 4

f(4)=1/4*4+8=1+8=9

Now we can draw the function.

graph{(y-1/4x-8)(x^2+(y-8)^2-0.5)((x-4)^2+(y-9)^2-0.5)=0 [-32.47, 32.46, -16.23, 16.25]}

Nov 25, 2017

A quick and easy way to graph a line is to plot the x and the y intercepts.

Explanation:

The intercepts lie on the line where one of the values is 0.
That makes it easy to solve for the other value just by looking -- no math necessary.
.......................

The y intercept must be the place where x equals 0, which is the ordered pair (0,y)

To let x equal 0, just put your fingertip over the mx term and hide it.
It would have dropped out to zero anyway.
Then solve the equation in your head.
f(x)=(1)/(4)x+8

Cover the mx term (which is zero) with your fingertip and solve for y
f(x)= ░░ +8

This gives you the ordered pair (0,8), which is tthe y intercept.
...........................

The x intercept must be the place where y equals 0, which is the ordered pair (x,0).

To find this point rapidly, cover the y term with your fingertip.
It would have ended up as zero anyway.
Then solve for x in your head.

░░ =(1)/(4)x+8
- 32 = x

This gives you the ordered pair (-32,0), which is the x intercept.
.....................

Now you have two useful ordered pairs that you can find without doing any math.

(0,8) larr the y intercept
(-32,0) larr the x intercept