# What is the equation of the line perpendicular to y=21/4x  that passes through  (-3,5) ?

Apr 12, 2016

4x + 21y = 93

#### Explanation:

In the form y = mx + c for the equation of a straight line, m gives the slope of the line.

For any line perpendicular to this line, the slope is the negative reciprocal $- \frac{1}{m}$.

Here, m = $\frac{21}{4}$. $- \frac{1}{m} = - \frac{4}{21}$.
So, the equation of the perpendicular line through (-3, 5) is y-5 = (/4/21)(x + 3)#.

This can be rearranged as 4x + 21y = 93.