How do you graph -8x+10y=40 using intercepts?

2 Answers
Mar 26, 2017

see explanation.

Explanation:

To find the color(blue)" x and y intercepts"

• " let x = 0, in the equation, to find y-intercept"

• " let y = 0, in the equation, to find x-intercept"

x=0to10y=40rArry=4larrcolor(red)" y-intercept"

y=0to-8x=40rArrx=-5larrcolor(red)" x-intercept"

Plot the points (0 ,4), (-5 ,0) and draw a straight line through them for the graph.
graph{4/5x+4 [-11.25, 11.25, -5.625, 5.625]}

Mar 26, 2017

Plug in 0 for x to find the y-intercept, and 0 for y to find the x-intercept. Then, graph these two points on a coordinate plane and connect them.

See below for the solution with graph.

Explanation:

Keep in mind that the x-intercept is the point where y is 0, and the y-intercept is the point where x is 0.

It's easier to remember this if you think about the intercepts on a graph - any point on the y-axis has to have an x coordinate of 0, or else it wouldn't be on the y-axis (and vice versa).

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

First, find the x-intercept by plugging in 0 for y.

-8x + 10(0) = 40
color(white)"XXXX--"-8x = 40
color(white)"XXXXXX.." x = -5

The x-intercept, then, is color(red)("(-5, 0)

Next, find the y-intercept by plugging in 0 for x.

-8(0) + 10y = 40
color(white)"XXXXX-"10y=40
color(white)"XXXXXX.."y=4

The y-intercept, then, is color(blue)("(0, 4))

Finally, to graph the line, just graph these two points, and connect them, as shown below.

![desmos.com/calculator](useruploads.socratic.org)