When you have a negative exponent, you move the base with the negative exponent to the other side of the fraction to make the exponent positive.
For example:
or 
or 

When a base with an exponent is divided by a base with an exponent, you subtract the exponents together. (But you can only combine the exponents when the bases are the same)
For example:
(can't combine because they have different bases of y and x)


When you multiply an exponent directly to a base with an exponent, you multiply the exponents together.
For example:


First multiply the exponents together in the denominator
Now subtract the exponents together
(two negative signs cancel each other out and become positive)

