xy-x^2乘以xy x-y-搜答案-智慧作业帮

把13X^2-6XY+Y^2-4x+1=0配方,得13X^2-6XY+Y^2-4x+1=09x^2-6xy+y^2+4x^2-4x+1=0(3x-y)^2+(2x-1)^2=0又因为(2x-1)^2>

x/y=3所以x=3y(x²+2xy-3y²)/(x²-xy+y²)=(9y²+6y²-3y²)/(9y²-3y&sup

(x-y)²=(x+y)²-4xy=36+8=44x-y=±√44=±2√11于是（x^4-y^4）除以x^2+y^2/xy乘以（6x+6y）=（x²+y²)(

已知xyx+y＝2

∵xyx+y=2∴xy=2（x+y）∴原式=3x−5×2(x+y)+3y−x+3×2(x+y)−y=−7x−7y5x+5y=−75

XY(XY-X^2)(X-Y)=X^2Y(X-Y)(X-Y)=(X-Y)(X^2Y-1)再问：答案是。-X2Y.我不知道过程是如何来的。能告诉我过程吗。谢谢。负X的平方Y

对.前提是x不等于y

a-b=-xy+3y^2-x^2-3a+2b=42x^2-4y^2

由题意得方程组x-2=正负2的平方=4y+3=3^3=27所以x=6y=24把x=6y=24代人x*(x-2xy+y)*y=6*(2-2*6*24+24)*24=-37152

解；已知正数x，y满足，x2+y2=1，则1=x2+y2≥2xy，∴xy≤12…① 又xyx+y=11x+1y≤12 1x•1y=xy2…②①②联立得xyx

=(xy-x的平方）除以(x的平方-2xy+y的平方\xy)乘以(x-y\x的平方)=-x（x-y）×xy/（x-y）²×（x-y）/x²=-y

∵xyx+y=-2，yzy+z=43，zxz+x=-43，∴1x+1y=-12，1y+1z=34，1z+1x=-34，∴2（1x+1y+1z）=-12，即1x+1y+1z=-14，则xyzxy+yz+

原式=(3x²+7xy+2y²)(x-2y)=(3x+y)(x+2y)(x-2y)=(3x+y)[x²-(2y)²]=(3x+y)(x²-4y

证明函数f(x,y)=(x+y)/(x-y)在点(0,0)处的二重极限不存在.当点(x,y)沿着直线y=kx(k为不等于1的任意实数)趋于(0,0)时,limf(x,y)=lim(x+kx)/(x-k

x(y-x)÷(x²-2xy+y²)/xy×(x-y)/x²=-x(x-y)×xy/(x-y)²×(x-y)/x²=-y

2+x^2+(x^2)*(y^2)=2X-2xy,化简得：（x-1)^2+(xy-1)^2=0【把化简前式子中的2分成1+1】所以x-1=0,xy-1=0,得x=y=1【（x-1)^2是（x-1)的平

把分式xyx+y中的x和y都扩大2倍后得：2x•2y2(x+y)=4xy2(x+y)=2•xyx+y，即分式的值扩大2倍．故选：B．

(x/x+y+2y/x+y)乘以xy/x+2y除以(1/x+1/y)=(x+2y)/(x+y)*xy/(x+2y)/[(x+y)/(xy)]=xy/(x+y)*xy/(x+y)=(xy)^2/(x+y

xy³+xy²+xy=xy(y²+y+1)

（2X的平方Y-XY）乘以3XY=6X³Y²-3X²Y²

（xy-x²）÷xy分之x²-2xy+y²乘x²分之x-y=-x(x-y)×xy/(x-y)²×(x-y)/x²=-y∴结果与x的值没有关系