已知x\3=y=z\2,且x+y+z=12,求2(x)的平方+12（y）的平方+9(z)的平方的值

已知x,y,z都是正数,且xyz=1,求证：x^2/(y+z)+y^2/(x+z)+z^2/(x+y)≥3/2 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 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 已知x:y:z=2:3:4,且x-y+z=36,求x+y+z的值. 已知x:y:z=2:3:4且x+z-y=36求x+y+z的值 已知x:y:z=2:3:4,且x+z-y=36.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)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? 已知方程组{X+Y-7Z=0(1)3X-2Y-Z=0(2)且Z不等于0求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))/xyz 已知x+y/2=y+z/3=z+x/4,且x+2y+z=12,求x-2y+z的值 已知X+Y/2=Y+Z/3=Z+X/4,且2X+4Y+6Z=120,求X,Y,Z的值 已知x+y/2=y+z/3=x+z/4 且2x+4y+6z=120,求x、y、z的值 已知x=y/3=z/5.且x+y-2z不等于0.求2x+3y-z/x+y-2z的值是多少 已知x/2=y/3=z/4,且x+y+z不等于0,求2x+3y-4z/x+y+z的值 已知方程组{2x-3y+z=0 且x*y*z不等于0 求 x：y：z {3x-2y-6z=0 已知x/2=y/3=z/4,且x+y+z不等于0,求2x+3y-4z/x+y+z的值