x^2(x+2)-(x+2)=0
(x^2-1)(x+2)=0
（x+√2)(x-√2)(x+2)=0
x= √2 或 -√2 或 -2x^2(x+2)-(x+2)=0(x^2-1)(x+2)=0（x+1）（x-1）（x+2）=0x1=-1 x2=1 x3=-2聪明，聪明，初一化简的题目吧