If k, n, x and y are positive numbers satisfying and , what is in terms of n and k?

Thanks in advance!! (:

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- September 28th 2008, 05:31 AMfabxx[SOLVED] SAT math page 674 #19
If k, n, x and y are positive numbers satisfying and , what is in terms of n and k?

Thanks in advance!! (: - September 28th 2008, 05:42 AMskeeter
this will get you started ...

now do the same to solve for y in terms of n ... then evaluate - September 28th 2008, 06:42 AMfabxx
- September 28th 2008, 06:52 AMMoo
- September 28th 2008, 07:05 AMskeeter
my apologies ... I assumed you had some knowledge regarding the Laws of Exponents

- September 28th 2008, 07:42 AMshailen.sobhee
Basically,

If its SATs,, forget about complex rules.*AS A RULE*

...(1)

and

... (2)

From (1),

Cross multiply and shift the x-term to the left hand side, you get:

... (3)

Multiply (2) and (3)

Squaring on both sides and making a reciprocal of the left-hand and the right-hand-side term gives:

<= Answer - September 28th 2008, 07:46 AMfabxx
i got x=k^(8/3) and y=n^(3/2)

If i substitute I have

How do i solve after this?

Like this? : but how do i get the final answer - September 28th 2008, 08:06 AMskeeter
had to fix my original post ... had the fraction flipped.

should be

so, you should get ...

- September 28th 2008, 09:06 AMshailen.sobhee
Find shortcuts - do not solve for x. See my steps how I got the answer.

Hope that helps. - September 28th 2008, 10:31 AMfabxx
Thanks to all three of you, I know how to do it now. Thanks guys. You guys were very helpful!!