How do you solve the equations if the exponent is negative

ANSWER
A. 1/9
EXPLANATION
When we have an expression with a negative exponent we can solve it by "flipping" the fraction and solving with the positive exponent:
[tex]\mleft(\frac{a}{b}\mright)^{-c}=\mleft(\frac{b}{a}\mright)^c[/tex]In this problem we have to find:
[tex]f(-2)=3^{-2}[/tex]We can think of a whole number as a fraction whose denominator is 1:
[tex]f(-2)=\mleft(\frac{3}{1}\mright)^{-2}[/tex]So we can use the trick:
[tex]f(-2)=\mleft(\frac{1}{3}\mright)^2[/tex]And solve:
[tex]f(-2)=\frac{1}{3^2}=\frac{1}{9}[/tex]