CPM Homework Help : CALC Problem 4-10

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

Hint:

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 $x =3$ .

Step 1:

To find a point, evaluate $f(3)=$ _________

Step 2:

To find the slope, evaluate $f^\prime(3)=$ ________

Step 3:

Put it all together in point-slope form: $y-y_1 = m(x-x_1)$