3分之x y加2分之x-y=6 3(x y)-2(x-y)=28-搜答案-神马作文网

1/x+1/y=2(x+y)/xy=2x+y=2xy(2x-xy+2y)/(3x+5xy+3y)=[2(x+y)-xy]/[3(x+y)+5xy]=(4xy-xy)/(6xy+5xy)=3xy/11x

(y-x)/xy=3求（2x+3xy-2y)/(x-2xy-y)?(y-x)/xy=3-->1/x-1/y=3-->y-x=3xy（2x+3xy-2y)/(x-2xy-y)=(x-y)/(-5xy)=

分子分母同除以xy,分子变为2（1/x+1/y)+3=2x3+3=9分母变为（1/x+1/y)+2=3+2=5答案是9/5

xy分之x加y等于2∴x+y=2xy3x减5xy加3y分之负x加3xy减y=[-(x+y)+3xy]/[3(x+y)-5xy]=(-2xy+3xy)/(6xy-5xy)=xy/(xy)=1

答：1/x+1/y=3(x-2xy+y)/(2x+xy+2y)分子分母同除以xy得：=(1/y-2+1/x)/(2/y+1+2/x)=(3-2)/(3*2+1)=1/7

再问：2/5再答：？

x+y=-3x=-y-3xy=2(-y-3)y=2-y²-3y-2=0y²+3y+2=0（y+1）（y+2）=0y1=-1y2=-2一、当y1=-1时,x1=-2,根号y分之x加根

直接设X=1,Y=0.5.带入后式得出10

2*1=1/(2X1)+1/(2+1)(1+a)=7/12,=>a=3,3*1=1/(3X1)+1/(3+1)(1+3)=19/48

xy/(x+y)=2∴xy=2(x+y)(3xy-x-y)/(3x-5xy+3y)=[6(x+y)-x-y]/[3x+3y-10(x+y)]=5(x+y)/[-7(x+y)]=-5/7

x分之1减y分之1等于2（y-x）xy=2y-x=2xyy减xy减x分之3x加xy减3y=[3(x-y)+xy]/(y-x-xy)=(-6xy+xy)/(2xy-xy)=-5xy/xy=-5

此题简单做法你直接可以设X=1,Y=0.5,使其满足前面的条件即可,带入后面分式,后面的式子中文表述不清,

因为X+Y分之XY=2,所以XY=2(X+Y)代入后面的分子式得：13（X+Y)/5(X+Y)=13/5

3y/(2x+2y)+2xy/(x²+xy)=3y/(2x+2y)+2y/(x+y)=3y/(2x+2y)+4xy/(2x+2y)=7y/(2x+2y)

原式=[(x+2y)/(x+y)]×[xy/(x+2y)]÷[(x+y)/xy]=[(x+2y)/(x+y)]×[xy/(x+2y)]×[xy/(x+y)]=x²y²(x+2y)/

悬赏分给我

因为1/x+1/y=-3所以(x+y)/xy=-3即x+y=-3xy所以(x-6xy+y)/(3x+2xy+3y)=(-3xy-6xy)/[3(x+y)+2xy)]=-9xy/(-9xy+2xy)=9

已知xy/(x+y)=2,求:(3x-5xy+3y)/(-x+3xy-y)xy/(x+y)=2得：xy=2(x+y)(3x-5xy+3y)/(-x+3xy-y)=(3x-9xy+3y+4xy)/(-x

xy/(x+y)=2(x+y)/xy=1/21/x+1/y=1/2(3x-xy+3y)/(-x+3xy-y)=(3/y-1+3/x)/(-1/y+3-1/x)=[3(1/x+1/y)-1]/[(3-(

xy分之【x加y】等于2分之一xy=2(x+y)【xy加x加y】分之xy=2(x+y)/[2(x+y)+x+y]=2(x+y)/[3(x+y)]=2/3