(x+1减1-x分之1)除以(x减x-1分之x的平方)

问题描述:

(x+1减1-x分之1)除以(x减x-1分之x的平方)

(x+1-1/(1-X))/(X-X^2/(X-1))
=(-X^2/(1-X))/(-X/(X-1))
=X