y-x=2xy
3x+7xy-3y/2x-3xy-2y
=[3(x-y)+7xy]/[2(x-y)-3xy]
=(-6xy+7xy)/(-4xy-3xy)
=-1/7
那么(3x+7xy-3y)/(2x-3xy-2y)【同时除以xy】
=(3/y+7-3/x)/(2/y-3-2/x)
=(-2*3+7)/(-2*2-3)
=-1/7
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y/xy－x/xy＝2
(y－x)/xy＝2
y－x＝2xy
(3x＋7xy－3y)/(2x－3xy－2y)
＝[-3(y－x)＋7xy]/[-2(y－x)－3xy
＝[-3(2xy＋7xy]/[-2(2xy)－3xy]
＝(7xy－6xy)/(-4xy－3xy)
＝xy/(-7xy)
＝-1/7
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1\/x-1\/y=2 y-x=2xy 3x+7xy-3y\/2x-3xy-2y =[3(x-y)+7xy]\/[2(x-y)-3xy]=(-6xy+7xy)\/(-4xy-3xy)=-1\/7
已知1\/x - 1\/y = 2,求3x+7xy-3y \/ 2x-3xy-2y的值
1\/y=x\/xy. 则1\/x-1\/y=(y-x)\/xy=2.
已知1\/x - 1\/y = 2,求3x+7xy-3y \/ 2x-3xy-2y的ŀ
1\/x-1\/y=2 xy≠0 所求式子分子分母同时除以xy：(3x+7xy-3y)\/(2x-3xy-2y)=(3\/y+7-3\/x)\/(2\/y-3-2\/x)=[-3(1\/x-1\/y)+7]\/[-2(1\/x-1\/y)-3]=[-3×2+7]\/[-2×2-3]=1\/(-7)=-1\/7
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因为 1\/x - 1\/y = 2，即 (y-x)\/xy = 2 所以y - x = 2xy 所以 (3x+7xy-3y) \/ (2x-3xy-2y)= 1 + (x + 10xy - y) \/ (2x - 3xy - 2y)= 1 + 8xy \/ -7xy = 1 - 8\/7 = -1\/7
已知X分之一减Y分之一等于2求3X加4XY减3Y分之2X减3XY减2Y的值
解：已知x分之1-y分之1=2，得xy分之y-xy分之x=2 xy分之（y-x）=2 y-x=2xy x-y=-2xy 则（3x+4xy-3y）分之（2x-3xy-2y）=[（3x-3y）+4xy]分之[（2x-2y）-3xy]=[3×（x-y）+4xy]分之[2×（x-y）-3xy]=[3×（-2xy）+4xy]分之[2×（-2xy）-3xy]=（-6xy+4xy...
已知x分之一减y分之一等于2,求X+3XY-Y分之3x-xy-3y的值
由x分之一减y分之一等于2 化简得：X—Y=-2XY X+3XY-Y分之3x-xy-3y=X+3XY-Y分之X+3XY-Y+2X-4XY-2Y=1+(X+3XY-Y)分之2X-4XY-2Y 用X-Y=-2XY代入上面的公式中，最后得出结果为：-7
已知1\/x-1\/y=2,求分式x-2xy-y\/2x-3xy-2y的值
1\/x-1\/y (y-x)\/xy=2 y-x=2xy x-2xy-y\/2x-3xy-2y =(-2xy-2xy)(-4xy-3xy)=(-4xxy)\/(-7xy)=4\/7 不懂可追问，有帮助请采纳，谢谢！
已知x分之1-y分之1=2,求2x-3xy-2y分之x-2xy-y的值.
∵1\/x-1\/y=2 ∴(y-x)\/(xy)=2 ∴y-x=2xy ∴2x-3xy-2y=2(x-y)-3xy=-4xy-3xy=-7xy x-2xy-y=x-y-2xy=-2xy-2xy=-4xy ∴(x-2xy-y)\/(2x-3xy-2y)=(-4xy)\/(-7xy)=4\/7 即答案为4\/7 不懂得欢迎追问.
x分之1 - y分之1=2 求分式2x+7xy-2y 分之 -x+xy+y
1\/x-1\/y=2,通分得(y-x)\/xy=2,则y-x=2xy 代入所求的分式可得：-2（y-x）+7xy=3xy y-x+xy=3xy 所以所求分式=1
已知1\/x-1\/y=3,则式子2x 7xy-2y\/x-2xy-y的值为
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