The next problem is a fraction with a negative exponent on top, but only positive exponents on the bottom:

The x^{-2} on top of the fraction bar is moved below it, and its
exponent is changed from negative two to positive two.
Since there is already x^{2} on the bottom, they are multiplied together.
The number 1 is left on the top of the fraction because, as you may recall,
when a term does not have an explicit coefficient, it has an implicit
coefficient of 1.

The next page links to various negative exponent resources.