Question

先化简,后求值：（x+1分之1+x的平方-1分之x的平方-2x+1）除以x+1分之x-1

Answer 1

[1/(x+1)+(x^2-2x+1)/(x^2-1)]÷（x-1)/(x+1)

=[1/(x+1)+(x-1)^2/(x+1)(x-1)]*(x+1)/(x-1)

=[1/(x+1)+(x-1)/(x+1)]*(x+1)/(x-1)

=[x/(x+1)]*(x+1)/(x-1)

=x/(x-1)