已知(x-5)分之A+(x+2)分之B=(x^2—3x—10)分之(5x—4),求A、B的值

A/(x-5)+B/(x+2)=(5x-4)/(x^2-3x-10)
左边＝A(x+2)/(x-5)(x+2)+B(x-5)/(x-5)(x+2)
＝(Ax+2A+Bx-5B)/(x^2-3x-10)
所以A+B=5
2A-5B=-4
A=3 B=2