Simplify: ab+baab−ba\frac{\frac{a}{b} + \frac{b}{a}}{\frac{a}{b} - \frac{b}{a}}ba−abba+ab
a2+b2a2−b2\frac{a^2 + b^2}{a^2 - b^2}a2−b2a2+b2
111
a+ba−b\frac{a + b}{a - b}a−ba+b
aba2−b2\frac{ab}{a^2 - b^2}a2−b2ab