Ahh yes, negative exponents always give us a scare once and a while. All the negative means is to flip the position of its base. For instance, if x has a negative exponent and x in the denominator, all you would have to do is move x to the numerator with the same power (except it's no longer negative). Before we substitute x and all the other variables which the values given, let's eliminate the negatives first.
After flipping positions/eliminating the negative exponents it should look like this:
which simplifies to
now that everything is simplified, and all negative exponents are eliminated we can substitute x with 2, and y with (-4).
which simplifies to
Final Answer: - \frac{1}{32} [/tex]