解:原式 = - x^6 - x^5 + x^4 - x^3 + x^2 + 2x - 1
= - x^6 - x^5 + x^4 +x^3 - 2x^3 - 2x^2 + 2x^2 + 2x + x^2 - 1
= - x^5(x+1) + x^3(x+1) - 2x^2(x+1) + 2x(x+1) + (x-1)(x+1)
= - (x+1)( x^5 - x^3 + 2x^2 - 3x +1)