What is -a^-2 if a = -5

A. -25
B. 25
C. -1/25
D. 1/25

1 answer

To find -a^-2, we substitute a = -5 into the expression:

-a^-2 = -( -5 )^-2

Since a negative number raised to an even exponent is always positive, we have:

-( -5 )^-2 = -(-5)^-2
= -1/(-5)^2
= -1/25

Therefore, the answer is C. -1/25.