已知x+2y+3z=54,3x+y+2z=47,2x+y+z=31,则式子x+y+z的值是
已知x+2y+3z=54,3x+y+2z=47,2x+y+z=31,则式子x+y+z的值是
已知x^3+y^3-6x+2y+z+3+10=0,求(x-y+z)(x+y-z)的值.(z+3)是绝对值
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2x=3y=4z求2x-y+z分之x+y+z的值
已知x:y:z=2:3:4,且x-y+z=36,求x+y+z的值.
已知x/4=y/5=z/6 求x+y+z/3x-2y+z的值
已知x/4=y/5=z/6,求x+y+z/3x-2y+z的值.
已知{x:y:z=1:2:3,x+y+z=12,求x、y、z的值
已知x:y:z=2:3:4,且x+y+z=18,求x,y,z的值
已知x:y:z=2:3:4求x-y+z分之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