Question

What is the slope of any line perpendicular to the line passing through `(-9,8)` and `(-1,1)`?

Answer 1

`m'=8/7`

Explanation:

First find the slope of this line:

`m=(y_2 - y_1)/(x_2-x_1)`

`m=(1 - 8)/(-1-(-9))`

`m=-7/8`

formula for a perpendicular slope is `m'=-1/m`

`m'=-1/(-7/8) = 8/7`

Answer 2

`8/7`

Explanation:

find the slope of the two given points
from the two points slope formula:

`m = (y_2-y_1)/(x_2-x_1)`

`(-9,8) " and " (-1,1)`

`x_1=-9`

`x_2=-1`

`y_1=8`

`y_2=1`

`m = (1-8)/(-1-(-9)) = -7/8`

perpendicular slope means the reciprocal in the opposite sign

so `8/7`