(-10)^-1

Question

A. -1/10
B. -1/1^10***
C. 1/10
D. 10

I had a little trouble when I started these. Can someone explain this to me?

Answer 1

a^-n = 1/a^n

so (-10)^-1 = 1/(-10^1 = -1/10

Answer 2

Thanks.