已知X分之1 Y分之1=X Y分之5,求X分之Y Y分之X的值

1/X+1/Y=3即x+y=3xy(2x+3xy+2y)/(x-2xy+y)=(2*3xy+3xy)/(3xy-2xy)=9xy/xy=9答案为9

解1/x+1/y=5即(y+x)/xy=5∴y+x=5xy∴(2x+3xy+2y)/(x-2xy+y)=[2(x+y)+3xy]/[(x+y)-2xy]=[2×5xy+3xy]/(5xy-2xy)=(

由1/x-1/y=3得(y-x)/xy=3题中的式子分子分母同时除以xy得(2/y+3-2/x)/(1/y-2-1/x),通分得【2(x-y)/xy+3】/【(x-y)/xy-2】代入得3/5

1/x-1/y=2(y-x)/xy=2y-x=2xy所以x-y=-2xy原式=[2(x-y)+7xy]分之[(y-x)+xy]=[2(-2xy)+7xy]分之[(2xy)+xy]=3xy]分之3xy=

1/x-1/y=2001则(x-xy-y)/(x-y)=2002/2001

∵1/x+1/y=1/6,1/y+1/z=1/9,1/z+1/x=1/15∴（1/x+1/y）+（1/y+1/z）+（1/z+1/x）=1/6+1/9+1/152（1/x+1/y+1/z）=15/90

已知x分之1-y分之1=3,则有y-x=3xy(5x+xy-5y)/(x-xy-y)=7/2

1/x-1/y=3x-y=-3xy(2x+3xy-2y)/(x-2xy-y)=[2(x-y)+3xy]/[(x-y)-2xy]=(-3xy)/(-5xy)=3/5

1/x-1/y=3(2x+3xy-2y)/(x-2xy-y)=(2/y+3-2/x)/(1/y-2-1/x)=[3-2(1/x-1/y)]/[-2-(1/x-1/y)]=(3-2*3)/(-2-3)=

(x-3xy-y)分之(2x+3xy-2y)分子分母同时除以xy得=(1/y-3-1/x)分之(2/y+3-2/x)=[-(1/x-1/y)-1]分之(-2(1/x-1/y)+3)=(-3-1)分之(

由x分之1-y分之1=2得到,1/x-1/y=2,即（y-x）/(xy)=2,即x-y=-2xy(1).2x-3xy-2y分之3x+7xy-3y=(2x-3xy-2y)/(3x+7xy-3y)(2)将

(5x+3xy-5y)/(x-2xy-y)=(5/y+3-5/x)/(1/y-2-1/x)分子分母同时除以xy=[-5(1/x-1/y)+3]/[-(1/x-1/y)-2]=(-15+3)/(-3-2

1/x-1/y=(y-x)/xy=3y-x=3xy所以x-y=-3xy所以原式=[(x-y)-2xy]分之[2(x-y)-5xy]=[(-3xy)-2xy]分之[2(-3xy)-5xy]=(-5xy)

1/x+1/y=-2则(x-xy+y)/(x+xy+y)分子分母同除以xy=(1/x+1/y-1)/(1/x+1/y+1)=(-2-1)/(-2+1)=3

(x分之1)+(y分之1)=5（x+y)/xy=5x+y=5xy代入（x+2xy+y)分之(2x-3xy+2y)=7xy分之7xy=1

x-y分之xy=-3分之1xy分之(x-y)=-3x-y=-3xyx-2xy-y分之2x+3xy-2y=(-6xy+3xy)/(-3xy-2xy)=3/5

已知：1/X-1/Y=5通分：(Y-X)/XY=5,倒数：XY/(Y-X)=1/5.

由已知条件可得：x-y=-4xy,（也就是在等式两边乘xy后整理,即可）,代入所求的式子里分母为-4xy+7xy,即3xy；分子为-4xy-2xy,即-6xy,化简得-2

x分之1-y分之1=-3所以(y-x)/xy=-3y-x=-3xy从而3x-2xy-3y分之x+3xy-y=（3xy+3xy）/(3×3xy-2xy)=6/7

分子上应写：（x-1）²或者x²-2x+1再问：怎么书面表达呢？能否详细一些，谢谢再答：希望你及时采纳！！！！！