### Home > PC3 > Chapter 4 > Lesson 4.1.1 > Problem 4-21

4-21.

Factor.

This is the difference of two perfect squares.

Factor out the greatest common factor. Then factor again since you have a binomial with two perfect cubes.

Factor out

.

4-21.

Factor.

This is the difference of two perfect squares.

Factor out the greatest common factor. Then factor again since you have a binomial with two perfect cubes.

Factor out

.