How do you find the important points to graph y=-2x-3?

1 Answer
Nov 10, 2015

Find the points at which the line crosses the x and y axes.

Explanation:

x intercept
When a point is on the x axis, we know its y value is 0. This means we can make the equation equal to 0 to find x.

0 = -2x -3

3 = -2x (add 3 to both sides)

3/2 = -x (divide by 2 on both sides)

-3/2 = x (times both sides by -1)

This means x = -3/2 or x = -1.5 So our x intercept is at the coordinate (-1.5, 0)

y intercept
On the y axis we know the x value is equal to 0, so we can substitute this into the equation to find the y value.

y = -2(0) - 3

y = -3 (remove anything multiplied by 0)

So we now know our y intercept is at (0,-3)

So the important points are (-1.5, 0) and (0, -3)