Answer:
[tex]k=-2[/tex]
Step-by-step explanation:
Let's write the left hand side as a negative power, and 9 as a power of 3:
[tex]3^-^k=3^2[/tex] At this point, for the equality to still stand, the exponents have to be equal:
[tex]-k = 2 \rightarrow k=-2[/tex]
