Need help on evaluating expression.

R

RHSLilSweetie07

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Sep 25, 2005
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The problem is as follows:

[(x*2y^-1*z^-2)/(x*y^3*z^-4)]^-3

The first thing I did was flip the fraction and made the outer exponent positive. Then I cubed every term in the fraction to get the following:

(x^3*y^9*z^-12)/(x^3*8y^-3*z^-6)

Have I done everything right so far?

From there on out, I canceled out the x's and made the negative exponents positive:

(8*y^12*z^6)/(z^12).

My answer was (8*y^12)/(z^6), but my teacher told me it was wrong. Please help me realize where I messed up. :oops:
 
You've posted this to "calculus", instead of to one of the "algebra" categories. Are you supposed to be differentiating or something...?

Your subject line refers to "evaluating", which says that you need to plug given numbers in for the variables and simplify to get the answer, but you didn't provide those numbers...?

Please clarify. Thank you.

Eliz.
 
I agree with your second expression. You're good to that point. But the "8" has no negative exponent on it, so there's no reason for it to move with the y<sup>-3</sup>. The y-factor will move, but the 8-factor stays where it is.

Fix that, and you should be fine.

Eliz.
 
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