# What is the slope of a line perpendicular to the line whose equation is y = 2x + 5?

May 24, 2016

$- \frac{1}{2}$

#### Explanation:

The slope, or gradient, of the line $y = 2 x + 5$ is 2.

If 2 lines are perpendicular, their gradients multiply to -1.

Let us call the perpendicular gradient m.

$2 \times m = - 1$

$m = - \frac{1}{2}$

Therefore, the slope, or gradient, of the perpendicular line is$- \frac{1}{2}$