已知xy不等于0-搜答案-智慧作业帮

原式=(y-x)/xy=-xy/xy=-1

移项,x=y+xy:同除y得x/y=1+x;同除X得1/y=1/x+1;移项1/x-1/y=-1

x+2y=0x=-2y2xy+y2/x2-xy=-4y^2+y^2/4y^2+2y^2=-5/6

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=(3x+4y)(x-2y)=0so3x+4y=0orx-2y=0x/y=-4/3or2

x+2y=0x=-2y2xy+y2/x2-xy=-4y^2+y^2/4y^2+2y^2=-5/6

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

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.

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

(1/x)-(1/y)=(y-x)/xy=-xy/xy=-1

xy不等于0所以x≠0,y≠03x^2-2xy-8y^2=0两边除以y^2=>3(x/y)^2-2(x/y)-8=0=>[(x/y)-2][3(x/y)+4]=0=>x/y=2,或x/y=-4/3

2分之1或负4分之3

2x²-xy-2y²=0两边同除以x²得：2-(y/x)-2(y/x)²=0(y/x)²+1/2(y/x)=1(y/x+1/4)²=1+1/

2x2+5xy-3y2=0(2X-Y)(X+3Y)=0==>X=Y或者X=-3YXY不等于0,即X,Y都不等于0所以X:Y=X/Y=1或者-1/3

无解

因为,x-y=3xy所以：-3x+6xy+3y/[(7x-5y)-9xy-(3x-y)]=[-3(x-y)+6xy]/[(7x-5y)-9xy-(3x-y)]=[-3*3xy+6xy]/[7x-5y-

x^2+xy-6y^2=0化简得（x-2y)(x+3y)=0x=2y或x=-3y分别带入2x^2-3xy+y^2/5x^2-7xy+2y^2化简即可.