Simplify: a2−b2a+b⋅1a−b\frac{a^2 - b^2}{a + b} \cdot \frac{1}{a - b}a+ba2−b2⋅a−b1 (assume a≠±ba \neq \pm ba=±b).
1
a−ba - ba−b
a+ba + ba+b
1(a+b)\frac{1}{(a+b)}(a+b)1