expand, equate to zero and find value of x from 1 to about 3 or so, that can give zero when substituted.
x= -2 gives 0
then do long division: x+2 into x^3 - x^2 -9x - 6
(x+2)(x^2-3x-3)=0 , use quadratic formula for the 2nd bracket as it cant be factorized
x = -2 or x= 3.79 or x= -0.79