a/(x-2)+1/(x²-4)+2=0
乘以x²-4得
a(x+2)+1+2(x²-4)=0
2x²+ax+2a-7=0
有增根,则x=2或x=-2
将x=2代入,得
8+2a+2a-7=0
4a=-1
a=-1/4
将x=-2代入,得
8-2a+2a-7=0
1=0不成立
所以
a=-1/4