1/10x加y等于77 10x y=1265-搜答案-智慧作业帮

X²+Y²=10..(1)X+Y=6..(2)(2)²-(1)得2XY=26XY=13如果认为讲解不够清楚,

x^2+2x+y^2-6y+10=0=(x^2+2x+1)+(y^2-6y+9)=0=(x+1)^2+(y^2-6y+3^2)=0=(x+1)^2+(y-3)^2=0x=-1y=3xy=-3

x²+xy=2xy+y²=-1两式相减得：x²-y²=3两式相加得：x²+2xy+y²=1

1/X+1/Y=（X+y）/xy=1/xy=原式xy＞0x+y=1≥2根号xy即xy≤0.25则1/xy≥4则1/xy≥8-1/xy则1/X+1/Y≥8-1/xy

7/12

原式=√（2x+1）+(y-2)^2=02x+1=0,y-2=0解得：x=-1/2,y=2xy=(-1/2)*2=-1

x+y=3/2可得x=（3/2）-yxy=y*[（3/2）-y]=1解得y不存在所以原方程组无实根【如果题没错的话.

直接设X=1,Y=0.5.带入后式得出10

若X>1,y>0,且满足xy=x^y,x/y=x^(3y)相乘得x2=x^(4y)y=0.50.5x=根号x0.25x2=xx=4x+y=4.5

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,

那就会等于-7X+5(X+Y)-3xy-10y=5(x+y)-10XY-10Y=5(x-y-2xy)=-35再问：7X去哪里了，10xy那一步没看懂再答：打错了，应该是-7XY+5(X+Y)-3xy-

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

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)/

解题思路：此题主要考查了完全平方公式的应用；解答时整体求解xy解题过程：解：∵x+y=6∴(x+y)2=36即：x2+2xy+y2=36∵x2+y2=12∴12+2xy=3

3∵x/y=1/2∴y=2x故（x^2+2xy+y^2)/(x^2-xy+y^2)=(x+y)^2/(x^2-xy+y^2)=(x+2x)^2/(x^2-x·2x+4x^2)=9x^2/(3x^2)=

xy=0.5×【（x-y）-x-y】=1-9=-8

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

如果x的平方加xy等于2,y的平方加x的y等于-1,则x的平方-y的平方=?x的平方加2xy加y的平方等于多少?x²+xy=2y²+xy=-1x²+xy-y²-

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