化简：(a−a/a+1)÷a2−2aa2−4×1/a+2
问题描述：
化简：(a−
)÷a a+1
×
a2−2a
a2−4
1 a+2
答
(a−
)÷a a+1
×
a2−2a
a2−4
1 a+2
=(a−
)×a a+1
×(a+2)(a−2) a(a−2)
1 a+2
=(a−
)×a a+1
1 a
=a×
−1 a
×a a+1
1 a
=1−
1 a+1
=
．a a+1