Question

9^-3/2?

Answer 1

This is best solved by simplifying the indexes
9^(-3/2) = (3^2)^(-3/2)

Now, the
=>^(-3/2) part means the 'square root of the inverse cubed'

this corresponds to

sqrt(3^2)^(-3) = 3^-3

which due to the minus is 1/(3^3)

which is 1/27