Anything raised to the zeropower is 1 . So k^0 = 1 and you can forget about it.
The expression is now (-3)^-4 .
Anything raised to the -4 power means 1 / (the same thing raised to the 4 power).
So (-3)^-4 means 1 / [ (-3) · (-3) · (-3) · (-3) ] .
If you slog through that, you should end up with 1 / 81 .
You really ought to slog through it, for the practice.