positives and negatives

[vivekjaiswal]

Hi Guys,

I stumbled into this strange problem...any thoughts for the best possible approach on this one?

Each of the following equations has at least one solution EXCEPT

A. -2^n = (-2)^-n

B. 2^-n = (-2)^n

C. 2^n = (-2)^-n

D. (-2)^n = -2^n

E. (-2)^-n = -2^-n

OA A

[grockit_jake]

With exponents, remember that you flip the fraction in the base to eliminate the negative in the exponent.

I think the best strategy would be to quickly eliminate all the negatives from the exponents by flipping the fractions. This will make it visually easier.

2 other things to remember are that when the negative is outside of the (), then that term MUST be negative, since 2 to any power must be positive. If the - is inside the (), then depending on the odd/even designation of the exponent, the sign will alternate.