# What is the equation of the normal line of #f(x)=-7x^3-x^2-x-1# at #x=-8#?

##### 1 Answer

Dec 14, 2015

#### Explanation:

Hence the slope of the tangent at

But the normal is perpendicular to the tangent and hence the slope of the normal at that point is

But the normal line is a straight line so of form

Substituting the point

Thus the normal has equation