(a2-1)/(a2+2a+1)除以(a2-a)/(a+1) (a-2/(a+3)除以(a2-4)/(a2+6a+9)
=﹙a²-1﹚/﹙a²+2a+1﹚×﹙a+1﹚/﹙a²-a﹚×﹙a-2﹚/﹙a+3﹚×﹙a²+6a+9﹚/﹙a²-4﹚
=﹙a+1)(a-1)/(a+1)² ×(a+1)/a(a-1) ×(a-2)/(a+3) ×(a+3)²/(a+2)(a-2)
=a+3/a﹙a+2﹚ (约分后)
(a2-1)/(a2+2a+1)除以(a2-a)/(a+1) (a-2/(a+3)除以(a2-4)/(a2+6a+9)
=﹙a²-1﹚/﹙a²+2a+1﹚×﹙a+1﹚/﹙a²-a﹚×﹙a-2﹚/﹙a+3﹚×﹙a²+6a+9﹚/﹙a²-4﹚
=﹙a+1)(a-1)/(a+1)² ×(a+1)/a(a-1) ×(a-2)/(a+3) ×(a+3)²/(a+2)(a-2)
=a+3/a﹙a+2﹚ (约分后)