若1⼀x-1⼀y=1,求3y-xy-3x⼀x-xy-y的值。

若1/x-1/y=1,求3y-xy-3x/x-xy-y的值。
2024-12-12 16:54:02
推荐回答(2个)
回答1:

1/x-1/y=1
xy/x-xy/y=xy
y-x=xy
∴3y-xy-3x/x-xy-y=3(y-x)-xy/(x-y)-xy
=3xy-xy/-xy-xy
=2xy/-2xy
=-1

回答2:

y-x=xy
原式=【3xy-xy】/【-xy-xy】=2/[-2]=-1