# What is the equation of the line normal to #f(x)=(5+4x)^2 # at #x=7#?

##### 1 Answer

Apr 15, 2018

#### Explanation:

A normal line is a line that is perpendicular to the tangent line of a graph at the point of tangency.

Let's find

When

With this in mind, let's find the point of tangency.

The normal line will have the slope of

We use the slope-intercept form: