Question

A line on the coordinate plane passes through the points (7, -5) and (3, 11). A line that is perpendicular to the first line passes through the points (-3, -9) and (5, n). Find the value of n.

Answer 1

Slope of the line passing through (7,-5) and (3,11) =
$\frac{11 - ( - 5)}{3 - 7}$
= -4

As two lines are perpendicular to each other, so when their slopes are multiply by each other, the answer will be -1

so the slope of the line passing through (-3,-9) and (5,n) will be
$\frac{1}{4}$
So will will get a formula below
$\frac{n - ( - 9)}{5 - ( - 3)} = \frac{1}{4}$
and the answer will be n=
$- 7$