x.y>0,且x y=4求x分之一 y分之3的最小值

x-4√xy-5y=0(√x+√y)(√x-4√y)=0√x=4√yx=16y(x+√xy-y)/(2x+√xy+3y)=(16y+4y-y)/(32y+4y+3y)=19y/39y=19/39

x-3y=0且xy≠0,所以x=3y(x≠0,y≠0)带入分式,(9y-3y+y)/(9y+3y+y)=7/13

X+（根号XY）-6Y=0(根号X+3根号Y)(根号X-2根号Y)=0根号X+3根号Y=0或根号X-2根号Y=0根号X=-3根号Y（舍)或根号X=2根号Y解得X=4Y(4X+5Y)/(X-Y)=(4*

x-5xy+6y=0(√x-2√y)(√x-3√y)=0所以√x=2√y,√x=3√yx=4y或x=9y原式=(8y)/(9y)=8/9或=(14y)/(20y)=7/10

答：x-7y=0x=7y≠0所以：x/y=7,y/x=1/7(x²-3xy+y²)/(2x²﹢xy-3y²)=(x/y-3+y/x)/(2x/y+1-3y/x)

xy-12=4x+y≥2√(4xy)=4√(xy)xy-4√(xy)-12≥0(√(xy)-6)(√(xy)+2)≥0√(xy)≤-2,√(xy)≥6因为√(xy)≥0所以√(xy)≥6xy≥36所以

因为x-y=4xy所以x-2xy-y=2xy2x+3xy-2y=11xyx-2xy-y分之2x+3xy-2y=5.5

xy再问：不够详细啦！最好有列式什么的！拜托了啊！再答：。。。。。这怎么列呀一看就知道了再问：你的答案怎么不一样啊？(⊙o⊙)…列一下啦！拜托拜托了！再答：那你自己看着办吧再问：好吧！O(∩_∩)O哈

（根号x-根号y）/（根号x+根号y）=根号【（x+y-2根号（xy））/（x+y+2根号（xy））】=根号【（5-4）/（5+4）】=1/3

x+根号xy-6y=0(根号x-2根号y)(根号x+3根号y)=0解得根号x=2根号y即x=4y或根号y+3根号y=0不成立所以4x+5根号xy-6y分之x+2根号xy=[4y+2根号(4y*y)]/

根号x等于2倍根号yx=4yX-Y分之4X+5Y等于7

1.若x分之1-y分之1=2,则求x-xy-y分之3x+xy-3y=0的值.若x分之1-y分之1=2变形（y-x）/xy=2,(y-x)=2xy(3x+xy-3y)/(x-xy-y)=[3(x-y)+

已知x>y且x+y=5xy=4(x-y)^2=(x+y)^2-4xy=5^2-4*4=9x-y=3∴根号x-根号y分之根号x+根号y=(根号x+根号y)(根号x+根号y)/[(根号x-根号y)(根号x

再问：太草率了吧。。直接写报纸上⊙▽⊙再答：不好意思，好久没学习了再问：。。。再答：等回头我买个本子去…再问：。。再问：不至于吧。。再答：哈哈

2x²-xy-3y²=0(x+y)(2x-3y)=0x=-y(舍去)或x=3y/2x/y=3/2x/y-x²/(x-y)=x/y-x²/(x²-2xy

因为x>0,y>0,所以将x-根号xy-2y=0因式分解得(根号x-2根号y)(根号x+根号y)=0所以根号x=2根号y,即x=4y后面请自己代入吧,我看不懂你的表述.不好意思了

①xy同非负时,2x-3√xy-2y=(2√x+√y)(√x-2√y)=0∴√x=2√y,x=4y②xy同负时,2x-3√xy-2y=[2√(-x)+√(-y)][√(-x)-2√(-y)]=0∴√(

1.x=1,y=1,√xy+y分之x+√xy=12.将△DFC绕点D顺时针旋转180°,得到△DGB,连接EG.则△DFC≌△DGB.所以FD=DG,BG=FC,角FDC=角BDG有因为DE.DF分别

∵x-y=4xy∴原式=[2(x-y)+3xy]/[-(x-y)-2xy]=(8xy+3xy)/(-4xy-2xy)=11xy/(-6xy)=-11/6