(1)X+Y=15,Y+Z=-6,Z+X=7.(2)X+Y=-14,Y+Z=-7,Z+X=9.(3)X+Y=0,Y+Z=
(x+y-z)(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)
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
y+z÷x=Z+X÷y=X+Y÷z,X+Y+Z不等0求X+Y-Z÷X+Y+z值
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
已知:(x+y-z)/z=(x-y+z)/y+(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z)
f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w)
如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y,
已知x、y、z满足方程组:x+y-z=6;y+z-x=2;z+x-y=0 求x、y、z的值
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
x/2=y/3=z/5 x+3y-z/x-3y+z