### Home > CALC > Chapter 3 > Lesson 3.3.3 > Problem 3-122

3-122.

Find all values of *x* where *f *′(*x*) = 2 given

Since *f*(*x*) is cubic, *f* '(*x*) will be quadratic. Predict how many solutions there will be to *f* '(*x*) = 2.

The blue curve shows *f* '(*x*) intersecting the dotted line *y* = 2. Do your solutions look correct?

Use the Power rule to find *f* '(*x*).

Set *f* '(*x*) = 2, and solve for *x*.

Use the eTool below to explore the graph of *f*(*x*).

Click the link at right for the full version of the eTool: Calc 3-122 HW eTool