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Algebra question

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by sibbineni » Sun Aug 03, 2008 5:53 pm
5^21 * 4^11 = 2 * 10^n

5^21*2^22=2 * 10^n

5^21*2*2^21=2 * 10^n

2*5^21*2^21=2*10^n

(5*2)^21=10^n

10^21=10^n

as bases are equal equating the exponents

n=21

IMO B
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hmm

by blueland78 » Sun Aug 03, 2008 9:48 pm
what ever happened to 2^21 at the second to last step????
I cant see it..@.@
SJ
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by pepeprepa » Mon Aug 04, 2008 1:41 am
To go from this one to the other:
2*5^21*2^21=2*10^n
(5*2)^21=10^n
You have to know that k^a*m^a=(km)^a
Look at your math review.
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by sibbineni » Mon Aug 04, 2008 3:07 am
2*5^21*2^21=2*10^n

5^21*2^21=10^n
here by applying the following formula a^n*b^n=(ab)^n

(5*2)^21=10^n

10^21=10^n
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