CPM Homework Help : CALC Problem 7-163

Multiple Choice: The normal line to the curve represented by the equation $y = x^2 + 6x + 4$ at the point ( $−2$ , $−4$ ) also intersects the curve at $x = ?$

$−6$

$-\frac { 9 } { 2 }$

$-\frac { 7 } { 2 }$

$−3$

$-\frac { 1 } { 2 }$

Hint:

A normal line is perpendicular to the tangent line, at the point of tangency.
So if you can find the tangent line, then you can also find the normal line.

Steps:

Let the equation of the normal line $= x^² + 6x + 4$ and find the TWO points of intersection.