A/3x+2-B/x-1
=[A（x-1）/(3x+2)(x-1)]-[B(3x+2)/(3x+2)(x-1)]
=[A（x-1）-B(3x+2)]/[(3x+2)(x-1)]
=(Ax-A-3Bx-2B)/(3x²-x-2)
=[(A-3B)x-(A+2B)]/(3x²-x-2)
则：{A-3B=4 ……①
A+2B=9……②
①-②,得-5B=-5,B=1
把B=1代入①,得A-3=4,A=7