Question

急！一道数学题！

已知X减Y等于3XY不等于0，则分式X加XY减Y分之5X减XY减5Y的值为？

Answer 1

huangborun，你好！
解：x-y=3xy≠0
(5x-xy-5y)/(x+xy-y)
=[5(x-y)-xy]/(x-y+xy)
因为x-y=3xy
所以上式=(15xy-xy)/(3xy+xy)
=14xy/4xy
=7/2

Answer 2

x-y=3xy

(5x-xy-5y)/(x+xy-y)
=[5(x-y)-xy]/(x-y+xy)
=(5*3xy-xy)/(3xy+xy)
=14xy/4xy
=7/2

Answer 3

将X-Y=3XY代入得
（5X-XY-5Y)/（X+XY-Y)=(5*3XY)/(3XY+XY)=15/4