A/x-2+B/x-5
=(AX-5A+BX-2B)/(X-2)(X-5)
=[(A+B)X-(5A+2B)]/(X-2)(X-5)
而它又等于4X+1/(x-2)(x-5)
即 4=A+B
1=-(5A+2B)
解得：A=-3,B=7
你能明白,赞同