Hello,

I am trying to find the critical numbers for

f'(x) = 36x^3 - 72x^2 - 72

I got it to:

36(x^3 - 2x^2 - 2)

However, I am confused to as if I am supposed to factor it more?

Or how would I solve for

36(x^3 - 2x^2 - 2) = 0

Thanks very much in advance.