### Home > CALC > Chapter 4 > Lesson 4.2.1 > Problem4-47

4-47.

Use the Power Rule to find $f^\prime(x)$ for $f(x) = (x^2 + 1 )(x-4)$ by first expanding $f(x)$. Then, find the equation of the line tangent to $f(x)$ at $x =-3$.

Write the tangent line in point-slope form.

Which function, $f(x)$ or $f^\prime(x)$, can be used to find the slope? Which can be used to find the point?