Question

Find an equation of the line that goes through the points (-9,-20) and (-8,-17). Write your answer in the form y = m x + b .

Answer 1

y = 3x + 7

Explanation:

First, we will solve for the slope (m).

The formula for slope is: m =
`(y2 - y1)/(x2 - x1)`

m =
`(-17 - -20)/(-8 - -9)` --- enter the points into the formula

m =
`(3)/(1)` --- simplify

m = 3 --- simplify

Now we will solve for the y-intercept (b).

y = mx + b

y = 3x + b --- substitute the slope into the equation

-20 = 3(-9) + b --- substitute the x and y of either point into the equation

-20 = -27 + b --- simplify

7 = b --- add 27 to both sides

b = 7

Done.

y = 3x + 7