已知,3x=2y不等于0,求分式x的平方-4xy 4y的平方

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

x²-5xy+6y²=0(x-2y)(x-3y)=0x=2y,x=3y所以x/y=2,x/y=3

3x²-2xy-8y²=0两边同除y²得:3(x/y)²-2(x/y)-8=0(3x/y+4)(x/y-2)=0x/y=2或x/y=-4/3

x/2=y/3=z/4=kx=2k,y=3k,z=4k2x+3y-4z/x+y+z=(4k+9k-16k)/(2k+3k+4k)=-1/3再问：确定？

x平方+2xy-8y平方=0(x+4y)(x-2y)=0x=-4y或x=2y(1)当x=-4y(x-y)/(x+y)=(-5)/(-3)=5/3(2)当x=2y(x-y)/(x+y)=1/3

(1)由题意：ay+bx=xyxy-bx=ay(y-b)x=ay(b≠y)x=ay/(y-b)(2)由题意：kx=xy-9-mxxy-mx-kx=9x(y-m-k)=9x=9/(y-m-k)

因为xy不为0,所以3x^2-2xy-8y^2=0可以两边同时除以y^2,得3(x/y)^2-2(x/y)-8=0即(3x/y+4)(x/y-2)=0解得x/y=2或者x/y=-4/3希望有用.

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

3x²-2xy-8y²=0(x-2y)(3x+4y)=0x=2y或3x=-4yx/y=2或x/y=-4/3

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，

2x-y+z=0上式两边同时除以x可得y/x-z/x=2标注为①x-2y+3z=0上式两边同时除以x刻碟2y/x-3z/x=1标注为②联解①与②可得y/x=5,z/x=3所以(x²+3y&#

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/

(1)4x-3y-3z=0,(2)x-3y+z=0,(1)-(2)3x=4z;z=3/4x(1)+3(2)7x=12y;y=7/12x,x:y:z=12:7:9

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

4x-3y+z=0(1)x+2y-8z=0(2)(1)-(2)×4得-11y+33z=0∴y=3z把y=3z代入(2)得x=2z把x=2z,y=3z代入x+y-z/x-y+2z得原式=(2z+3z-z

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

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/