x^3+y^3+z^3-3xyz变成(x+y+z)(x^2+y^2+z^2-xy-yz-xz)步骤
x^3+y^3+z^3-3xyz变成(x+y+z)(x^2+y^2+z^2-xy-yz-xz)步骤
已知x^3+y^3-z^3=96,xyz=4,x^2+y^2+z^2-xy+xz+yz=12,则x+y-z等于
已知x+y+z=3,xy+yz+xz=-1,xyz=2,求x^2y^2+y^2z^2+x^2z^2
xy/x+y=1 yz/y+z=2 xz/x+z=3 求xyz/x+y+z=?
分式题:xy=x+y,yz=2(y+z),zx=3(z+x),求xyz/(xy+yz+xz)
(2X+Z-Y)/(X^2-XY+XZ-YZ)-(Y-Z)/(X^2-XY-XZ+YZ)
已知x>0,y>0,z>0,证明x^3/(x+y)+y^3/(y+z)+z^3/(z+x)≥(xy+xz+yz)/2
xy/x+y=1,yz/y+z=2,xz/x+z=3求x,y
已知三个数x,y,z,满足xy/x+y=-2,yz/y+z=4/3,zx/z+x=-4/3,求(xyz)/(xy+yz+
已知三个数x,y,z满足xy/x+y=-2,yz/y+z=4/3,zx/z+x=-4/3,则xyz/xy+yz+xz=
已知三个数x,y,z,满足xy/x+y=-2,yz/y+z=3/4,zx/z+x=-3/4 ,则xyz/xy+xz+yz
已知x,y,z是实数,且xyz=1,求证x^2+y^2+z^2+3大于等于2(xy+xz+yz)