原式=2/(x-1) ÷[2/(x+1)(x-1) +(x-1)/(x+1)(x-1)]=2/(x-1)÷(2+x-1)/(x+1)(x-1)=2/(x-1)× (x-1)=2原式=(a+1)/(a-1)² ÷[(a-1)/(a-1) +2/(a-1)]=(a+1)/(a-1)²÷[(a-1)+2]/(a-1)=(a+1)/(a-1)²×(a-1)...