已知x/1-y/1=3,求：3x+xy-3y/x-y-xy的值额………………sorry，应该是1/x-1/y=3!

已知x/1-y/1=3,求：3x+xy-3y/x-y-xy的值额………………sorry，应该是1/x-1/y=3!
已知x/1-y/1=3,求：3x+xy-3y/x-y-xy的值
额………………sorry，应该是1/x-1/y=3!

已知x/1-y/1=3,求：3x+xy-3y/x-y-xy的值额………………sorry，应该是1/x-1/y=3!
已知条件不对吧?

∵x/1-y/1=3
∴y-x=3xy
3x+xy-3y/x-y-xy
=[3(x-y)+xy]／[(x-y)-xy]
=9xy+xy/3xy-xy
=10xy/2xy
=5/1