What is the greatest common factor of
4^17 - 2^28
2
3
5
7
11
OA: D
I broke this down into 2^34 - 2^28
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What is the greatest common factor of 4^17 - 2^28
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truplayer256
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You're on the right track.
2^34-2^28
2^28(2^6-1)
2^28(63)
63 is divisible by the prime factor 7. Therefore, 7 is our answer.
2^34-2^28
2^28(2^6-1)
2^28(63)
63 is divisible by the prime factor 7. Therefore, 7 is our answer.
-
doclkk
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I knew it.truplayer256 wrote:You're on the right track.
2^34-2^28
2^28(2^6-1)
2^28(63)
63 is divisible by the prime factor 7. Therefore, 7 is our answer.
darn.
I know how to do that - i've done that a million times. darn darn it.
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Ian Stewart
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The question should read "what is the greatest prime factor of 4^17 - 2^28". We only ever talk about 'common factors' when we are talking about two or more numbers. This question is about a single number.
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