x² 3xy-4y²=0 求x

1、2x+3y=0,得x=-3/2y5x+4y/3x-2y=（-15/2y+4y）/（-9/2y-2y）=7/132、x²+xy-y²/x²-xy+y²={(x

由|X-2|+(Y+1/4)^2=0绝对值大于等于0平方也是大于等于0所以X=2Y=-1/4带入后面要求的式子得到等于0-17/8

3x*+xy-2y*=0（3x-2y）(x+y)=0那么x=2y/3或x=-yy/x=3/2或x/y=-1(x/y)-(y/x)-(x*+y*)/(xy)=(x/y)-(y/x)-(x/y+y/x)=

y-x-2xy=0y-x=2xyx-y=-2xy(3x+xy-3y)/(y-xy-x)=[3(x-y)+xy]/[(y-x)-xy]=(-6xy+xy)/(2xy-xy)=-5xy/xy=-5

x^+2xy+y^+4=16(x+y)²=16-4=12(1)x^-2xy+y^=16(x-y)²=16(2)(1)-(2)2y*2x=-4xy=-1(3xy+6y^)+|x^-(

因为x-y=4xy所以x-2xy-y=2xy2x+3xy-2y=11xyx-2xy-y分之2x+3xy-2y=5.5

(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)=-6xy+3x-3y=-6×(-2)+3×1=15

3x^2+xy-2y^2=0推出(3x-2y)(x+y)=0推出x=-y或x=(2/3)y{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}/x^2-9y^2推出：{

（4xy+12y)+[7x-(3xy+4y-x)]=4xy+12y+7x-3xy-4y+x=xy+8x+8y=xy+8(x+y)=(-2)+8*3=-2+24=22

（x+2）^2+|x+y+5|=0,x+2=0,x+y+5=0x=-2,y=-33(x^2)y-2(x^2)y+2xy-(x^2)y+4x^2-xy=4x^2+xy=4*(-2)^2+(-2)*(-3

(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)=-2xy+2x+3y-3xy-2y+2x-x-4y-xy=-6xy+3x-3y=-6xy+3*(x-y)当时,原式=-6*1+3*

即(x-2y)²=0x-2y=0所以x=2y所以原式=(2x²+2xy-xy-y²)/(4x²-4xy+y²)=(2x²+xy-y²

3x+4y=0,即x=-4y/32xy+y²/x²-xy=2y(-4y/3)+y²/(-4y/3)²-(-4y/3)y=(-5/3)y²/(28/9)

y-x-2xy=0所以x-y=-2xyy-x=2xy所以原式=[3(x-y)+xy]\[(y-x)-xy]=[3×(-2xy)+xy]\(2xy-xy)=-5xy\xy=-5

①xy同非负时,2x-3√xy-2y=(2√x+√y)(√x-2√y)=0∴√x=2√y,x=4y②xy同负时,2x-3√xy-2y=[2√(-x)+√(-y)][√(-x)-2√(-y)]=0∴√(

2x＋y＋3=xy,①若x=1,则y不存在,此时5x＋4y无最值；②若x≠1,则y=(2x＋3)/(x－1),M=5x＋4y=5x＋(8x＋12)/(x－1)=(5x²＋3x＋12)/(x－

x+y=5xy（2x-3xy+2y)/(x+2xy+y）=[2（x+y）-3xy]/[(x+y)+2xy]=(2×5xy-3xy)/(5xy+2xy)=7xy/7xy=1再问：若x＋1/x＝3,求(x

2x-3√(xy)-2y=0(2√x+√y)(√x-2√y)=0因为x>0,xy≥0所以y≥02√x+√y>0所以√x-2√y=0,即x=4y(x^2+4xy-16y^2)/(x^2+xy-9y^2)

x+2=0,x+y+5=0x=-2,y=-33x^2y+{-2X^2y-[-2xy+(x^2y-4x^2)]-xy}=3x^2y-2X^2y+2xy-x^2y+4x^2-xy=4x^2+xy=4*4+

∵x-y=4xy∴原式=[2(x-y)+3xy]/[-(x-y)-2xy]=(8xy+3xy)/(-4xy-2xy)=11xy/(-6xy)=-11/6