2x^3+x^2-5x+2
=2x^3+x^2-x -4x+2
=x(2x^2+x-1)-2(2x-1)
=x(x+1)(2x-1)-2(2x-1)
=(2x-1)(x^2+x-2)
=(2x-1)(x-1)(x+2)