下列变形正确的是A 由X>Y 得XZ²>YZ² B 由XZ²>YZ² 得X>Y
xy-yz+xz-y²因式分解
已知x+y+z=1,x²+y²+z²=2求xy+yz+xz的值
已知x+y+z=10,xy+xz+yz=8,求x²+y²+z²的值
(2X+Z-Y)/(X^2-XY+XZ-YZ)-(Y-Z)/(X^2-XY-XZ+YZ)
已知X+Y+Z=a,XY+YZ+XZ=b,求X*X+Y*Y+Z*Z的值
已知x/3=y/4=z/6,求(xy+yz+xz)/(x²+y²+z²)
x/3=y/2=z/5,求xy+yz+xz/x²+y²+z²
已知x-y=1/2+√3,y-z=1/2-√3,求x²+y²+z²-xy-xz-yz的值
已知x-y=-1,z-y=2,求x²+y²+z²-xy-yz-xz的值
已知x/3=y分/4=z/5≠0求(3x²+4y²+5z²)/(xy+xz+yz)的值,
已知x+y+z=5,且xy+xz+yz=7,求x²+y²+z²的值
已知x:y:z=1:2:3,xy+yz+xz=66,求2x²+12y²-9z²的值.