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March 6th, 2014, 06:06 PM   #1
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cube root

What is the cube root of (81x^8y^12)?

It is probably super easy, but after several tries, I just give up. Thank you so much!!!

Given answers:

A) 3x^2y^4 cube root of (3x^2)
B) 3x^2y^4 fifth root of (3x^2)
C) 3x^2y^12 cube root of (3x^2)
D) 3x^2y^4 cube root of (3xy)
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March 6th, 2014, 06:29 PM   #2
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Re: cube root

The cube root of any product is the product of the cube root of each elements of the product.

That is:

Also and

Armed with that, you should be able to have another go.
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March 6th, 2014, 06:40 PM   #3
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Re: cube root

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March 6th, 2014, 07:13 PM   #4
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Re: cube root

When multiplying exponentials with the same base, add the exponents. The above uses that rule "in reverse".
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March 6th, 2014, 11:57 PM   #5
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Originally Posted by lila342
. . . after several tries, I just give up.
There are only four choices, and the second choice is absurd (the third choice also, if given a moment's thought), so how could you need more than three tries?
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