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trouble with exponents

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Re: trouble with exponents

by Morgoth » Mon Mar 16, 2009 4:56 am
feeet wrote:How can I solve this question?

What is n?
5^21 * 4^11 = 2 * 10^n

I know the answer is 21. How do I get there?

Thanks

Exponents keyword : SIMPLIFY


5^21 * 2^11 * 2^11 = 2 * 2^n * 5^n

5^21 * 2^22 = 2^(n+1) * 5^n


compare exponents since bases are same

compare the power raised to 2

n+1 = 22
n= 21

or

compare the power raised to 5

n=21


Hope this helps.
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