One of the rules of exponents is that you can move something from the numerator to the denominator or from the denominator to the numerator as long as you change the sign of the exponent. So if there is a 5∧9 in the denominator of the fraction we can move it to the numerator as long as we make the exponent from a 9 to a -9
I hope this helps and please don't hesitate to ask if there is anything still unclear!
