4^17 - 2^28Fab_Vr6 wrote:What is the greatest prime factor of 4^17 - 2^28
answers choices are: 2, 3, 5, 7, 11
= 4^17 - 4^14
= 4^14(4^3 - 1)
= 4^14 * 63
= 4^14 * 3 * 3 * 7
7 is the greatest prime factor
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jayhawk2001
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= 4^17 - 4^14
= 4^14(4^3 - 1)
= 4^14 * 63
= 4^14 * 3 * 3 * 7
7 is the greatest prime factor
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jayhawk2001
- Community Manager
- Posts: 789
- Joined: Sun Jan 28, 2007 3:51 pm
- Location: Silicon valley, California
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4^3 = 64. 64-1 = 63Fab_Vr6 wrote:jayhawk,
I don't quite get this part:
= 4^14(4^3 - 1)
= 4^14 * 63
