x-2y=-9{ y-Z=32Z+x=27
(x+y-z)(x-y+z)=
x-2y=-9{ y-Z=32Z+x=27
试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y)
X+Y+Z=?
(x+y-z)^2-(x-y+z)^2=?
分解因式:f(x,y,z)=x^2(y-z)+y^2(z-x)+z^2(x-y)
x,y,z为实数 且(y-z)^2+(x-y)^2+(z-x)^2=(y+z-2x)^2+(x+z-2y)^2+(x+y
x,y,z为实数且(y-z)平方+(x-y)平方+(z-x)平方=(y+z-2x)平方+(z+x-2y)平方+(x+y-
x/2=y/3=z/5 x+3y-z/x-3y+z
f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w)
已知 x,y,z都是正实数,且 x+y+z=xyz 证明 (y+x)/z+(y+z)/x+(z+x)/y≥2(1/x+1
解方程组1、4x+9y=12,3y-2z=1,2x+6z=32、3x-y+2z=3,2x+y-3z=11,x+y+z=1