x(x-2)+(2-x)=x(x-2)-(x-2)=(x-2)(x-1)请参考
x(x-2)+(2-x)=x(x-2)+(-1)(x-2)=x(x-2)-(x-2)=(x-1)(x-2)
x(x-2)=2-x x&78;-2x=2-x x&78;-x-2=0 (x+1)(x-2)=0 x=-1或2
