You can use the fact that a number raised to negative powers can be written as 1 divided by that number raised to positive number.
The value of the given expression when m = -5 and n= 3 is
Suppose we've got . then it can be rewritten as
It is because for any a except 0, and that
If base are same and there is multiplication, then there will be addition in power.
Also, know the fact that if base are same and there is division, there will be subtraction in power(subtracting since that denominator when goes up, its power gets negated(gets negative sign to the existing power)
Thus,
The given expression is
Putting m = -5 and n=3, we get:
Thus,
The value of the given expression when m = -5 and n= 3 is
Learn more about base and exponent(power) here: