1、原式=[(a+2)/(a-2)-2/(a-2)]÷(a²+2a)/(a-2)=a/(a-2)*(a-2)/(a²+2a)=1/(a+2)2、原式=[（x+1）/（x-1）+（1-x）/（x+1）]÷x/（x-1）=4x/（x^2-1）÷x/(x-1)=4/(x+1)
