When you have a negative power of a fraction, you can solve this way:
(5/6)^-4 = 5^-4/6^-4 = 6^4/5^4 = (6/5)^4
Another way to change a negative power of a fraction is to write the reciprocal of the fraction and change the power to positive.
(5/6)^-4=(6/5)^4
