x+y=-13 y+z=-15 z+x=-14
(x+y-z)(x-y+z)=
x+y+z=14,x'+y'+z'=15,(x-x')+(y+y')+z*z'=16,已知xyz为自然数,求x,y,z的
X+Y+Z=?
f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w)
2x+y+z=17 x+2z+y=14 x+z+2y=13 求:xyz
x y z x+y--- = --- = ---- ----y+Z z+x x+y ,求 z 的值 .求 x+y----
已知x+y-z/z=x-y+z/y=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz
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)
y+z÷x=Z+X÷y=X+Y÷z,X+Y+Z不等0求X+Y-Z÷X+Y+z值
(x+y-z)/z=(y+z-x)/x=(z+x-y)/y 求(x+y)(y+z)(z+x)/xyz
x分之y+z=y分之z+x=z分之x+y(x+y+z不等于0),求x+y+z分之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)