### Home > CALC > Chapter 8 > Lesson 8.1.4 > Problem 8-42

8-42.

Before integrating, make a choice:

or You could let *U* = 9 − 2*x*.

Don't forget the absolute value!

Notice the symmetrical bounds.Is this function odd? If so, the area will be 0. If not, integrate.

Factor before integrating.

*U*-substitution. Should *U* = sin*x* or *U* = cos*x*?