Answer
$(x-2)(x+1)(x-1)$
Work Step by Step
The product of a binomial sum and a binomial difference is: $(A+B)(A-B)=A^2-B^2$.
The square of a binomial sum is: $(A+B)^2=A^2+2AB+B^2$.
The square of a binomial difference is: $(A-B)^2=A^2-2AB+B^2$.
Hence here: $x^3-2x^2-x+2=\\=x^2(x-2)-(x-2)\\=(x-2)(x^2-1)\\=(x-2)(x+1)(x-1)$