A/x+1-B/ x-3=x+5/(x+1)(x-3) .求A=?B=?
问题描述：
A/x+1-B/ x-3=x+5/(x+1)(x-3) .求A=?B=?
答
A/(x+1)-B/(x-3)=(x+5)/(x+1)(x-3)
[A(x-3)-B(x+1)]/(x+1)(x-3)=(x+5)/(x+1)(x-3)
[(A-B)x-3A-B]/(x+1)(x-3)=(x+5)/(x+1)(x-3)
A-B=1
-3A-B=5
A=-1,B=-2