Seems to be easy question, but cant solve it
What is the greatest prime factor of 4^17-2^28 ?
2
3
5
7
11
OA: D
What is the greatest prime factor of 4^17-2^28 ?
2
3
5
7
11
OA: D
this is how i will solve it...bkobilov wrote:Seems to be easy question, but cant solve it
What is the greatest prime factor of 4^17-2^28 ?
2
3
5
7
11
OA: D
4^17-2^28 = 2^34 - 2^28
take 2^28 common, we get
=2^28(2^6-1)
=2^28(63)= 2^28 * 7 * 3^2
so the prime factors are 2,3, and 7
highest is 7
IMO: D
