Factor completely 3x3 - 3x2 - 18x.

3x (x + 3) (x + 2)

3x (x + 3) (x - 2)

3x (x - 3) (x + 2)

3x (x - 3) (x - 2)

Both 3 and x are common to all of the expressions so we can factor them out ...

3x^3 - 3x^2 - 18x

3x (x^2 - x - 6)

Now factor inside the parentheses

3x (x - 3) (x + 2)

Done. Answer C (or the 3rd one down)