An open Blog with tentative solutions and discussion of GMAT questions
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Tuesday, January 29, 2008
binomial factors
(2^2 - 1)( 2^2 + 1)( 2^4 + 1)(2^8 + 1)
A. 2^16 - 1 B. 2^16 + 1 C. 2^32 - 1 D. 2^128 - 1 E. 2^16.(2^16 - 1)
If you bear in mind that known property stating that (a-b)(a+b)=(a^2-b^2) you realise that the first two factors correspond to:
ReplyDelete(2^4 - 1).
Then, we now have only 3 factors:
(2^4 - 1).(2^4 + 1).(2^8 + 1)
Repeating the observation, the first two factors simplify to:
(2^8 - 1) x (2^8 + 1)
By the same property, we finally get:
(2^16 - 1)
:. Option A. is correct.
is result is actually similar th