Question

the lines are perpendicular if the slope of one line is -5 what is the slope of the other line

Answer 1

At first we should know that :

The product of the slope of the perpendicular lines = -1

Which mean if the slope of one of them is m and the slope of the other is m'

So,

$m\times m^{\prime}=-1$

Given : the slope of one line is = m = -5

So, the slope of the perpendicular line will be m'

So,

$\begin{gathered} -5\cdot m^{\prime}=-1 \\ \\ m^{\prime}=\frac{-1}{-5}=\frac{1}{5} \end{gathered}$

So, the answer is : the slope of the other line = 1/5