A(x+2)+B(x-5)=5x+4(A+B)x+(2A-5B)=5x+4A+B=52A-5B=4A=29/7B=6/7
解:左边化为(A+B)x+2A-5B=5x+4利用代定系数法得,A+B=5,2A-5B=4解得,A=29/7,B=6/7AB=174/49