Question

计算［a-（a/a＋1）］÷（a²-2a）/（a²-4）×（a＋1）/（a²＋3a＋2）

Answer 1

=[(a²+a-a)/(a+1)]÷[a(a-2)/(a+2)(a-2)]×[(a+1)/(a+1)(a+2)]

=a²/(a+1)÷a/(a+2)×1/(a+2)

=a²/(a+1)×(a+2)/a×1/(a+2)

=a/(a+1)