changingcourse Junior | Next Rank: 30 Posts View User Profile Posts: 22 Joined: Mon Feb 09, 2009 12:58 pm Prime factorization by changingcourse » Sun Dec 12, 2010 1:27 pm What is the greatest prime factor of 4^17 - 2^28 a) 2 b) 3 c) 5 d) 7 e) 11 Top Quote