x的平方-3x+2=0
(x-2)(x-1)=0
∴x=2或x=1
x+1分之x的平方-x乘x的平方-2x+1分之x的平方-1
=x(x-1)/(x+1)× (x+1)(x-1)/(x-1)²
=x
=2或1