What is the greatest prime factor of 8^11 - 2^30?	Answers:
A) 2  B) 3  C) 5  D) 7  E) 11
8^11 - 2^30   =(2^3)^11 - 2^30   = 2^33 - 2^30   = 2^30 (2^3 -1)   = 2^30 * (8-1)   = 2^30 * 7   The greatest prime factor is 7.   The answer is 7.
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What is the greatest prime factor of 8^11 - 2^30?