A/(x+1)+B/(x-2)=3/(x+1)(x-2) [A(x-2)+B(x+1)]/(x+1)(x-2)=3/(x+1)(x-2) A(x-2)+B(x+1)=3 Ax+Bx-2A+B=3 Ax+Bx=0 B-2A=3 A=-1 B=1