How can i simplify this one, please someone help me!

Combine the fractions and factorize.
[tex]\dfrac{3a^2b}{a-b} + \dfrac{3ab^2}{b-a} = \dfrac{3a^2b}{a - b} - \dfrac{3ab^2}{a - b} \\\\ ~~~~~~~~ = \dfrac{3a^2b - 3ab^2}{a - b} \\\\ ~~~~~~~~ = \dfrac{3ab (a - b)}{a - b} \\\\ ~~~~~~~~ = 3ab[/tex]