Question

What would make the bottom = 0

Answer 1

So you need x^5 - 81x = 0
x^5 - 81x = 0
Divide both sides by x
x^4 -81 = 0
Add both sides by 81
x^4 = 81
Take the 4th root of both sides
x = 3

That's your answer.

x = 0 would also work, which is another possible answer.

Have an awesome day! 

From your friendly Helper-in-Training, collinjun0827

P.S. Instead of saying "bottom", say "denominator"