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
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