通分
[A(X+2)-B(X-1)]/(X-1)(X+2)=(X+5)/(X-1)(X+2)
所以A(X+2)-B(X-1)=X+5
(A-B)X+(2A+B)=X+5
所以A-B=1 (1)
2A+B=5 (2)
(1)+(2)
3A=6
A=2
B=A-1=1
通分
[A(X+2)-B(X-1)]/(X-1)(X+2)=(X+5)/(X-1)(X+2)
所以A(X+2)-B(X-1)=X+5
(A-B)X+(2A+B)=X+5
所以A-B=1 (1)
2A+B=5 (2)
(1)+(2)
3A=6
A=2
B=A-1=1