已知(x+8)/(x-1)(x+2)=A/(x-1)+B/(x+2),求A,B的值

问题描述:

已知(x+8)/(x-1)(x+2)=A/(x-1)+B/(x+2),求A,B的值

两边乘以(x-1)(x+2)得 x+8=A(x+2)+B(x-1) =(A+B)x+(2A-B) ∴A+B=1 2A-B=8 ∴A=3 B=-2