# What is the slope of the line perpendicular to  y=8/5x-3 ?

Apr 30, 2018

$- \frac{5}{8}$

#### Explanation:

If you multiply the two gradients/slopes together the answer is -1 if they are perpendicular. So if you change the sign and take the reciprocal you have the second gradient.

Apr 30, 2018

$\text{perpendicular slope } = - \frac{5}{8}$

#### Explanation:

$\text{the equation of a line in "color(blue)"slope-intercept form}$ is.

•color(white)(x)y=mx+b

$\text{where m is the slope and b the y-intercept}$

$y = \frac{8}{5} x - 3 \text{ is in this form}$

$\text{with slope m } = \frac{8}{5}$

$\text{given a line with slope m then the slope of a line}$
$\text{perpendicular to it is}$

•color(white)(x)m_(color(red)"perpendicular")=-1/m

$\Rightarrow {m}_{\text{perpendicular}} = - \frac{1}{\frac{8}{5}} = - \frac{5}{8}$