# What is the equation of the line normal to #f(x)=x^2+8x - 12# at #x=3#?

##### 1 Answer

Jun 28, 2016

#### Explanation:

Given:

At

The slope of

At

If

then a line perpendicular to it (which the normal is) has a slope of

Therefore the normal to

passes through the point

Using the slope-point form for a line

Converting to standard form:

graph{(x^2+8x-12-y)(x+32y-675)=0 [-66, 65.6, -29, 36.85]}