What is
36x^3-33x^2-33x-6/9x+3
With parentheses properly inserted, it should read:
(36x^3-33x^2-33x-6)/(9x+3)
Try factorizing both numerator and denominator and cancel common factors, if possible:
(36x^3-33x^2-33x-6)/(9x+3)
=3(3x+1)(4x^2-5x-2)/3(3x+1)
=4x^2-5x-2