### Home > APCALC > Chapter 4 > Lesson 4.1.1 > Problem4-10

4-10.

Use the Power Rule to write and equation for $f^\prime$ if $f\left(x\right) = \left(x + 4\right)\left(x – 3\right)$ by first expanding $f$. Then, write the equation of the line tangent to $f$ at $x = 3$.

In order to find the equation of the tangent line at $x = 3$, you will need to find a point on the line and the slope at $x =3$.

To find a point, evaluate $f\left(3\right)= \text{ _________}$

To find the slope, evaluate $f^\prime \left(3\right)= \text{________}$

Put it all together in point-slope form: $y −y_{1} = m\left(x −x_{1}\right)$