Simplify: a3−b3a2−b2⋅a+ba2+ab+b2\frac{a^3-b^3}{a^2-b^2} \cdot \frac{a+b}{a^2+ab+b^2}a2−b2a3−b3⋅a2+ab+b2a+b.
111
a−ba+b\frac{a-b}{a+b}a+ba−b
a−ba−b\frac{a-b}{a-b}a−ba−b
a−ba-ba−b