Question

化简（x平方-2x+1分之x²-1+x+1分之1-x）除以x-1分之x的结果是多少?

Answer 1

原式={[(x+1)(x-1)]/(x-1)^2+(1-x)/(x+1)}÷x/(x-1)=[(x+1)/(x-1)-(x-1)/(x+1)] × x/(x-1)

=4x/(x-1)(x+1) × x/(x-1)=4/(x+1)