No solution question

[intrepid17]

Each of the following equations has at least one solution EXCEPT


a) -2power(n) = (-2)power(-n)


b) 2 power(-n) = (-2)power(n)

c) 2power(n) = (-2)power(-n)

d) (-2)power(n) = -2power(n)

e) (-2)power(-n) = -2power(-n)

[ps63739]

Question does not seem to be clear, can you please type the options correctly or provide a link to the question, please?

[tim]

i hate to say it, but sometimes it's quicker to plug in cleverly chosen numbers to eliminate wrong answers than to do the math for real. When you're dealing with powers, try 0 and 1 first:

B and C both give you 1=1 when n=0, in other words n=0 is a solution for B and C and thus we can eliminate them.

Similarly, 1 is a solution for both D and E, so we can eliminate them.

Proving that A actually has no solution is, frankly, beyond the level of math that the GMAT typically requires in its problems..

[shantascherla]

Tim I am stuck on this question.

Following your explanation - doesnt option 1 also give us the same result which is 1 when n = 0

[tim]

plug 0 into A and you get -2^0 for the left side. evaluate the power first and 2^0 = 1. now apply the negative and you get -1