Im stumped by these:

evaluate if possible:

-3√64 (the 3 is supposed to be in the dip of the square root symbol)

4√81 ( the 3 is also supposed to be in the dip of the square root sign)

3√1/125 ( " " )

The cube root of 64 is 4
The fourth root of 81 is 3
The cube root of 1/125 is 1/5