If ab 0, then a^(-1) + b^(-1) =

Question

If  ab ≠ 0 , then  a^{-1} + b^{-1}=

A. a + b 
B. -(a + b) 
C. 1/(a + b) 
D. 2/(a + b) 
E. (a + b)/ab

BrentGMATPrepNow · Answer

You might want to recheck your post. 
I think you meant to write "a" instead of "2"

Cheers, 
Brent

BrentGMATPrepNow · Answer

Key concept:  x^{-n}=\frac{1}{x^n}

a^{-1} + b^{-1} = \frac{1}{a}+\frac{1}{b}

= \frac{b}{ab}+\frac{a}{ab}

= \frac{b+a}{ab}

Answer: E

Cheers,
Brent

carbazzy · Answer

Thanks so much for all the replies. Made a ton of silly mistakes today!

TargetMBA007 · Answer

Bunuel  - Pls tag EA

Bunuel · Answer

_______________
Done. Thank you!

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