若x+y+z=3y=2z,则x/x+y+z=?
若{x+3y+10z=0 则 (x+y-z)/(x-y+z)
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)=
若x/3=y/2=z/5,则2x-3y-z/x-y+z=
x/2=y/3=z/5 x+3y-z/x-3y+z
X+Y+Z=?
若z分之x+y+z=y分之x-y+z=x分之-x+y+z,求xyz分之(x+y)(y+z)(z+x)
已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3
若x-2y+4z=1,x+3y-7z=0,则y:z=?
x=y/z=z/3,x+y+z =12,求2x+3y+4z是多少,
(x+y-z)^2-(x-y+z)^2=?
若3x+7y+z=5,4x+10y+z=3,则x+y+z=?