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# SAT exponent problem

edited September 2005
Here's an SAT type problem.... I don't really understand how they do it.

What is 1/2x^(-1/2) + 1/2x^(-3/2) equal to?

I don't get it. I have a feeling it's something simple I'm not seeing. Please help. Thanks.
edited September 2005
5 replies
Post edited by obsessedAndre on

## Replies to: SAT exponent problem

is it (1/2)x or (1)/(2x) ?
• 219 replies21 threads Junior Member
it's (1/2)x. Apparently this is a little hard...
• 2607 replies38 threads Senior Member
Rewrite the negative exponents as fractions. You have 1/(2x^(1/2)) + 1/(2x^(3/2)). You need to have a common demoninator to add the fractions, so multiply the first fraction by x/x to get x/(2x^(3/2)) + 1/(2x^(3/2)). Then add the numerators and get the answer: (x + 1) / (2*x^(3/2))
• 2301 replies228 threads Senior Member
First, please tell where you found it.

Factor (1/2)x^(-3/2) out:
1/2x^(-1/2) + 1/2x^(-3/2) =
(1/2)x^(-3/2) (x^(1) + 1) =
(1/2) (1/ x^(3/2)) (x + 1) =
(x + 1) 1/(2 x^(3/2)) =
(x + 1)/(2 x^(3/2))
Your intuition was telling you the truth.