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Exponents

by [email protected] » Thu Jul 31, 2008 9:52 am
If 2^b = 48^5/12^5, what is the value of b?

The way I did this was:

48^5 = (4*12)^5

so (4*12)^5/12^5 the 12^5's cross out

So you are left with (2^2)^5
which I thought was 2^7 so b is 7 but the answer is 10, can anyone explain please?

Thanks again!
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by Oxana » Thu Jul 31, 2008 9:56 am
48^5/12^5=4^5
4^5=2^5*2^5=2^10
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by sudhir3127 » Thu Jul 31, 2008 10:01 am
hey karen

u did everything correct ..only missed the last point

4^5 ca be writtenas (2^2)^5 which 2^10

( a^m)^n = a^m*n= a^mn

hope its clear now..
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by VP_RedSoxFan » Thu Jul 31, 2008 12:34 pm
this is a good time to refresh even myself on the exponent rules:

(a^m)^2 = a^(2m)

(ab)^2 = a^2 * b^2

(a+b)^2 = a^2 + 2ab + b^2

etc.

You did such a good job up until applying this rule, I hate to see hard earned points escape us...
Ryan S.
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by [email protected] » Thu Jul 31, 2008 12:58 pm
Thanks for all your responses definately wont male that mistake again :)
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