which expression is equivalent to this?

Answer:
45x^-10 or 45/x^10
Step-by-step explanation:
(3x^-4)^2 = 9x^-8
(9x^-8)*(5x^-2) = 45x10^-10
I don't see this answer in the options, but am wondering if the second one, 45/x10 is mistyped and is meant to be 45/x^10, which would be correct.