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)/(a+1)
=1/(a-1)
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)/(a+1)
=1/(a-1)