已知x不等于y,x^2-x=3 y^2-y=3,求x^2 xy y^2

x^2-x=3,y^2-y=3可知：x^2-x-3=0y^2-y-3=0所以x、y是方程a^2-a-3=0的两个不等的根.有x*y=-3,x+y=1则(x+y)^2=1=x^2+y^2+2xy结合x*

2x^2-3xy+y^2=(2x-y)(x-y)=0则可得2x=y或x=y①当2x=y时把2x=y代入其中得x/y+y/x=x/2x+2x/x=1/2+2=2.5②当x=y时x/y+y/x=x/x+x

x+y=根号2x+根号2y=y+根号2xx-y+根号2y-根号2x=0(x+y)(x-y)+根号2（y-x)=0(x-y)(x+y-根号2)=0x+y=根号2

已知x=y/3=z/5且x+y-2z不等于0那么y=3xz=5x（2x+3y-z）/（x+y-2z）=（2x+9x-5x）/（x+3x-10x）=6x/（-6x）=-1

x=3yz=7x=21y(x+y+z)/(2x+3y-z)=(3y+y+21y)/(6y+3y-21y)=25/(-12)=-25/12

已知x-y≠0,x²-x=7,y²-y=7,求x³+y³+x²y+xy²的值.经观察可知,x、y相当于是方程t²-t=7的两个不等

2x+5y+3z=0(1)2x-5y-8z=0(2)(1)-(2)10y+11z=010y=-11zy:z=-11:10=-22:20(1)+(2)4x-5z=04x=5zx:z=5:4=25:20所

y=(2x+1)/(x-3)={(2x-6)+7}/(x-3)=2+7/(x-3)x≠3在定义域内,x-3单调增,7/(x-3)单调减当x∈(-∞,3）时,7/(x-3)∈（-∞,0）,2+7/(x-

因为x^2+xy-2y^2=0所以x=-2yx=y(1)x=-2y所以x/y-y/x-(x^2+y^2)/xy=-2+1/2+5/2=1(2)x=yx/y-y/x-(x^2+y^2)/xy=1-1-2

X/X···这是什么意思···再问：x减y分之x等于x分之x减2y再答：两边同乘x（x-2y）再问：再答：题目是什么····就给个图啊···再问：如图，已知EFGH为矩形，AD⊥Bc于D，交HG于K，

∵X^2-X=3,Y^2-Y=3∴设k²-k-3=0,则x,y为这个方程的两个解xy=-3,x+y=1∴x²+y²=（x+y）²-2xy=1+6=7∴X^2+X

x=3yz=7x=7×3y=21y所以原式=(3y+y+21y)/(6y+3y-21y)=25y/(-12y)=-25/12

1.x^2-x=3,y^2-y=3∴x^2-x-3=0,y^2-y-3=0又∵x≠y∴x,y是方程z^2-z-3=0的两个不相等的根∴x+y=1,xy=-3∴x^2+xy+y^2=(x+y)^2-xy

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=-

如果是(x-y)/x=x/x-2y,则x:y=2:3(x-y)/x=（x-2y+2y）/x-2y1-y/x=1+2y/(x-2y)-y/x=2y/(x-2y)x/y=(x-2y)/-2yx/y=-1/

2x-3y=02x=3y3x/y=9/2所以(3x-2y)/y=9/2-2=5/2

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

无解

/>∵根号X²－3X－Y＝－X∴X²－3X－Y＝X²∴X／Y＝－1／3

2x²-xy-3y²=0(x+y)(2x-3y)=0x=-y,2x=3yx≠-y所以y=(2/3)x原式=(x²+2/3*x²)/(2/3*x²-4/