x^3+2x^2-x-2>0
(x^3+x^2)+(x^2-x-2)>0
x^2(x+1)+(x-2)(x+1)>0
(x+1)(x^2+x-2)>0
(x+1)(x-2)(x+1)>0
(x+1)^2*(x-2)>0
答案就不用说了吧