5x-2y-2=0XY等于多少-搜答案-大师作文网

x=3y=-1或x=-1y=3

2x^2+9xy+5y^2=0假设y不等于0,将方程两端同除以y^2,得：2（x/y）^2+9x/y+5=0解得：x/y=（-9+根号下41）/4或者（-9-根号下41）/4如果y=0,则y分之x不成

4xy加5x²y加yx²再问：谢谢了，

-5x+2-3xy-5y因为xy=1所以原式=-5x-5y-1-5（x+y)-1因为x+y=3所以-15-1=-16

-2,前提是xy都不为零再问：能说一下解题步骤吗？

由题意得，x+3=0，y-33=0，解得x=-3，y=33，所以，（-3×33）2013=-1．

[2x(x²y-xy²)+xy(xy-x²)]÷x²y=[2x²y(x-y)+x²y(y-x)]÷x²y=2(x-y)+(y-x)

x^2-2xy+y^2+y^2-y+1/4=0(x-y)^2+(y-1/2)^2=0(x-y)^2>=0(y-1/2)^2>=0(x-y)^2+(y-1/2)^2>=0(x-y)=0(y-1/2)=0

x^2-y^2/xy=x/y-y/x=2-1/2=1.5

你先设x/y=k,即x=yk所以原式=3k^2y^2+ky^2-4y^2=0即y^2(3k^2+k-4)=0因为y不能等于0,所以^2不等于0即3k^2+k-4=0得k=1(x不等于y,舍去）,K=-

2(x+xy)-[(xy-3y)-x]-(-xy)=2x+2xy-xy+3y+x+xy=3x+3y+2xy=3（x+y）+2xy=3*（-2）+2*3=0

3x²-xy+y²=101-xy+4y²=421-2得3x²-3y²=6x²-y²=2选B

1/x-1/y=3则x-y=-3xyx-3xy-y/2x-xy-2y=(-3xy-3xy)/(-6xy-xy)=6/7

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

(x+y)²=x²+2xy+y²=(x²-2xy+y²)+4xy=(x-y)²+4xy=49所以x+y=±7x²y+xy²

∵x=2,y=3∴2(xy^2+3y^3-x^2y)-(-2x^2y+y^3+xy^2)-4y^3=2xy²+6y³-2x²y+2x²y-y³-xy&

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

因式分解原式=[x(x-2)]/[-y(x-2)]=-x/y

f(x,y)=x*y^2+e^xfx(x,y)=y^2+e^xfx(0,1)=1^2+e^0=1+1=2