求2X— y+Z=6 x+y+2Z=3平面间的夹角.

已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, x+2y=3x+2z=4y+z 求x:y:z 已知：x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值. x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值 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满足方程组,X+y-Z=6y+z-x=2z+x-y=0求X.Y.Z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 求适合方程组 3x+2y-z=4 2x-y+2z=6 x+y+z 已知2x+5y+4z=6 3x+y-7z=-4求x+y-z 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. 5x+3y+2z=2011 4x+6y+7z=2012 求x+y+z x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. 若|x+3|+|y-2|+|2×z+1|=0求(x×z-y×z)(y-x+z)的值 方程组{x/2+y/3-z=-5,x/3-y/2+z/2=10,x/2-y/3-z/4=6,求x,y,z