# How do you find the slope that is perpendicular to the line  x - 2y = 7?

Sep 16, 2016

The slope of the line perpendicular to the given straight line is -2

#### Explanation:

Two striaght line are perpendicular if the product of their slopes is -1
Given the equation of the straight line
x−2y=7
-2y=7−x
$y = \frac{- x}{- 2} + \frac{7}{- 2}$
$y = \frac{x}{2} - \frac{7}{2}$
The slope of the given straight line is a=1/2 , the slope of the line perpendicular line a':

a⋅a'=−1
(1/2)*a'=−1
a'=−2