# What is the equation of the line perpendicular to #y=9/20x # that passes through # (-1,-5) #?

##### 1 Answer

Find the negative reciprocal of the slope of our given equation,

Keep in mind that **the slope of any line is defined as the negative reciprocal of the slope of the line that it is perpendicular to**.

The negative reciprocal of

This perpendicular line also lies on the point (-1, -5). With the coordinates of this point and the slope we previously found, we can construct our answer in **point slope form**:

In our case, m =

Now all we must do is to simply plug in our values:

If the question requires an equation in slope-intercept form, simply subtract 5 from both sides and simplify!