Having some trouble with this one.

My understanding so far is that if $\displaystyle x^-1 $ then it equals $\displaystyle 1/x$. Also that $\displaystyle x^1/2$ equals $\displaystyle sqrt x$.

The problem I am trying to simplify is $\displaystyle (81/16)^-3/4$.

I have simplified it to $\displaystyle 4sqrt (16/81)^3$

Can someone help me in the right direction please?

Not sure what the code for square root is in the math writing program either :S