Question

初二数学题.急！

已知2x+7/(x-1)(x+2)=A/x-1=B/x+2,其中A、B是常数，求A\B的值.

Answer 1

通分
=[A(x+2)+B(x-1)]/(x+2)(x-1)
=[(A+B)x+(2A-B)]/(x-1)(x+2)
=(3x-1)/(x-1)(x+2)
所以(A+B)x+(2A-B)=3x-1
A+B=3
2A-B=-1
A=2/3
B=7/3
A/B=2/7