Simplify.
-$\left( a ^ { - 1 } + b ^ { - 1 } \right) ^ { - 1 }$
A) $\frac { a b } { a - b }$
B) $\frac { a b } { a }$
C) $\frac { a + b } { a b }$
D) $\frac { a b } { a + b }$

Question

Quizplus · Accepted Answer

The expression simplifies to the reciprocal of the sum of the reciprocals of $a$ and $b$, which is $\frac{1}{\frac{1}{a} + \frac{1}{b}}$, further simplifying to $\frac{ab}{a+b}$.

Simplify - (a−1+b−1)−1\left( a ^ { - 1 } + b ^ { - 1 } \right) ^ { - 1 }(a−1+b−1)−1

Simplify
- $\left( a ^ { - 1 } + b ^ { - 1 } \right) ^ { - 1 }$