已知x-2y=0,求x²-y²分之y除以x-y分之1的值-搜答案-智慧作业帮

x^2+y^2+4x-6y+13=(x+2)^2+(y-3)^2=0所以x=-2y=3所以x^y=-8

(2x+y)/(x^2-2xy+y^2)X(x-y)=(2x+y)/（x-y）²*（x-y)=(2x+y)/（x-y）x-3y=0,x=3y(2x+y)/（x-y）=（6y+y）/（3y-y

2x-3y=0(1)3x-y-1=0(2)由（2）得y=3x-1(3)把y=3x-1代入(1)得2x-9x+3=0∴x=3/7把x=3/7代入（3）得y=2/7∴x=3/7y=2/7

x²+y²-2x+4y+5=0（x²-2x+1)+(y²+4y+4)=0(x-1)²+(y+2)²=0x-1=0x=1y+2=0y=-2x+

4x-2y=0→y=2x,把所有的y都用2x替代.结果是-1/7

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，

∵x²+y²-4x+2y+5=0x²-4x+4+y²+2y+1=0(x-2)²+(y+1)²=0x-2=0y+1=0∴x=2y=-14x&#

X+Y分之X-Y等于3x=-2yX+Y分之2(x-y)减X+Y分之3X+Y=(-x-3y)/(x+y)=1

2x=2-3yx>0则2x>0所以2-3y>0y

因为(x-y)/(x+y)=3,则(x＋y)/(x－y)＝1/3则5(x-y)(x+y)-(x+y)/2(x-y)＝5*3-1/(3*2)=15-1/6=89/6

x^2+2x+y^2-6y+10=0（x+1)²+（y-3)²=0∴x=-1,y=3(x+y)²=（-1+3）²=4

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：{

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

已知x^2+4y^2-4x+4y+5=0求(（y^4-x^4）/(y-2x)(x+y))*((2x-y)/(xy-y^2))/((x^2+y^2)/y)的值答案：x²+4y²-4x

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/

x²+4x+y²-2y+5=0x²+4x+4+y²-2y+1=0(x+2)²+(y-1)²=0所以x+2=0y-1=0则x=-2y=1所以x

解题思路：先利用完全平方公式求出x、y的值，再代入求出代数式的值。解题过程：

(x²－4x＋4)＋(4y²＋8y＋4)=0(x－2)²＋4(y＋1)²=0则：x－2=0且y＋1=0得：x=2、y=－1x＋y=1

√x方-y+√2x+y=0x²-y=0,2x+y=02x+x²=0x(x+2)=0x=0或x=-2x=0y=0x+y=0x=-2y=x²=4x+y=-2+4=2

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－