已知实数a满足a²+2a-8=0,求（a+1）分之1-（a²-1）分之（a+3）÷（a-1）分之（a+1）的值

已知实数a满足a²+2a-8=0,求（a+1）分之1-（a²-1）分之（a+3）÷（a-1）分之（a+1）的值
已知实数a满足a²+2a-8=0,求（a+1）分之1-（a²-1）分之（a+3）÷（a-1）分之（a+1）的值

已知实数a满足a²+2a-8=0,求（a+1）分之1-（a²-1）分之（a+3）÷（a-1）分之（a+1）的值
a²+2a-8=0
(a+4)(a-2)=0
a1=-4 a2=2
（a+1）分之1-（a²-1）分之（a+3）÷（a-1）分之（a+1）
=（a+1）分之1-（a²-1）分之（a+3）×（a+1）分之（a-1）
=（a+1）分之1-（a+1）分之（a+3）×（a+1）分之1
=(a+1)²分之(a+1)-(a+1)²分之(a+3)
=(a+1)²分之(a+1-a-3)
=-(a+1)²分之2
a=4时
原式=-25分之2
a=-2时
原式=-2

a²+2a=8
原式=1/(a+1)-(a+3)/(a+1)(a-1)×(a-1)/(a+1)
=1/(a+1)-(a+3)/(a+1)²
=(a+1-a-3)//(a+1)²
=-2/(a+1)²
=-2/(a²+2a+1)
=-2/(8+1)
=-2/9