If the original problem is not a fraction, like this:

 or 

Put in a 1 coefficient, then put it over 1, 
like this, so that it will be a fraction:

 or 

Next, if the negative exponent is in the numerator,
move it to the denominator, and change the negative
exponent to positive, like this

 or 

If the exponent is 1, just erase it.

--------------

If the negative exponent is a factor in the denominator, 
like this:



move it to the numerator and change the negative exponent to
positive, like this:

.

Edwin