how many posotive integer divide 2^7 x 3^8 such that they are not prime or 1,

thanks for any help

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- February 18th 2010, 03:34 AM #1

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- February 18th 2010, 04:04 AM #2

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- February 19th 2010, 05:33 AM #3

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- February 20th 2010, 08:56 AM #4

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Hello, hmmmm!

You got it!

How many positive integer divide such that they are not prime or 1?

There are 8 choices for the 2's: .

There are 9 choices for the 3's: .

Hence, there are: . choices for numbers of the form

But this includes: .

. . The rest are all composite.

Therefore, the answer is: .