X²-2XY加Y²加2X-2Y-3-搜答案-智慧作业帮

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

原式=（x+2y)^2-（x+2y）+1/4=0则x+2y=1/2

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

已知x平方加xy等于8,y平方加xy等于9,则x平方加y平方加2xy值是8+9=17

根据均值不等式x+2y≥2√[x*(2y)]=2√(2xy）,当且仅当x=2y取等两边平方得(x+2y)^2≥8xy……（*）将x=2y代入x+2y+2xy=8得x+x+x^2=8x^2+2x-8=0

直接设X=1,Y=0.5.带入后式得出10

x²+2xy+4y²+x²y²+1=8xy(x²-4xy+4y²)+(x²y²-2xy+1)=0(x-2y)²

x方+y方+5/4=2x+y(x方-2x+1)+（y方-y+1/4)=0(x-1)方+（y-1/2)方=0x=1,y=1/2xy/(x+y)=1/3

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,

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

这么简单都不会.直接猜就能猜出来了啊!X=2Y=根号3再问：拜托，你的答案是4+4根号3！再答：哈哈，原来本人在线的啊。。。你真聪明，你多大了？我都大一了，被你蒙了喇，呵呵！再问：12岁再答：现在读书

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)/

2+x^2+(x^2)*(y^2)=2X-2xy,化简得：（x-1)^2+(xy-1)^2=0【把化简前式子中的2分成1+1】所以x-1=0,xy-1=0,得x=y=1【（x-1)^2是（x-1)的平

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

x^2+2xy+y^2=(x^2+xy)+(xy+y^2)=2+7=9

x^2+2xy+y^2=(x^2+xy)+(xy+y^2)=2+7=9

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

=2倍（x-y）分之（x根号x-y根号y）+2根号xy.=(x-y)分之[2x根号x(1+根号y)-2y根号y(1+根号x)].