Set up an equation:
Numerator is the top number and denominator is the bottom number in a fraction.
(6x)^5 / d = 36
(6x)^5 can be rewritten as 6^5x^5
6^5x^5 / d = 36
Raise 6 tot he power of 5:
7776x^5 /d = 36
Multiply both sides by d:
7776x^5 = 36d
Divide both sides by 36:
d = 7776x^5 / 36
d = 216x^5