Answer
$a+b$
Work Step by Step
Multiply $\frac{ab}{ab}$ to the expression, we have:
$\frac{a^{-1}+b^{-1}}{(ab)^{-1}}=\frac{a^{-1}+b^{-1}}{(ab)^{-1}}\cdot \frac{ab}{ab}=\frac{b+a}{1}=a+b$
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.