Answer
$b-a$
Work Step by Step
Step 1: $\frac{\frac{b}{a}-\frac{a}{b}}{\frac{1}{b}+\frac{1}{a}}$
Step 2: $\frac{\frac{b^{2}-a^{2}}{ab}}{\frac{a+b}{ab}}$
Step 3: $\frac{(b+a)(b-a)}{ab}\div\frac{a+b}{ab}$
Step 4: $\frac{(b+a)(b-a)}{ab}\times\frac{ab}{a+b}$
Step 5: $\frac{(b+a)(b-a)}{a+b}$
Step 6: $b-a$