x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少,

x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, (x+y-z)(x-y+z)= X=3z X+y+z=12 X+2y-2z=10 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求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) X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) 3x-y+z=4,2z+3y-z=12,x+y+z=6的解 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)=? (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, 解方程 x(x+y+z)=6 y(x+y+z)=12 z(x+y+z)=18 解方程组{x(x+y+z)=6,y(x+y+z)=12,z(x+y+z)=18 x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z 已知x+y+z=0求证x*x*x+y*y*y+z*z*z=3xyz 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 x+y=8 y+z=12 x+z=10 x+y+z= x+y=8 y+z=12 x+z=10 x+y+z=