x^3-3x^2+4
=x^3-2x^2-x^2+4
=x^2(x-2)-(x^2-4)
=x^2(x-2)-(x+2)(x-2)
=(x-2)[x^2-(x+2)]
=(x-2)(x^2-x-2)
=(x-2)(x-2)(x+1)
=(x-2)^2(x+1)