(X+1)^2-2(X+1)=0 (x+1)(x+1-2)=0(x+1)(x-1)=0x=-1或x=1
(X+1)^2-2(X+1)=(X+1)(X+1-2)=(X+1)(X-1)=0X+1=0 or X-1=0X=1 or -1
X=正负1
