x+y+z=59,15x:12y=3:2,12y：8z=2:1谢

如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, 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=59,15x:12y=3:2,12y：8z=2:1谢 X=3z X+y+z=12 X+2y-2z=10 x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 x/2=y/3=z/5 x+3y-z/x-3y+z x+y/2=z+x/3=y+z/4 x+y+z=27 若x+y+z=3y=2z,则x/x+y+z=? x+2y=3x+2z=4y+z 求x:y:z 3x-y+z=4,2z+3y-z=12,x+y+z=6的解 方程组 (1) x+2y-3z=12 x-3y+2z= - 13 x-y-z=0 (2) x+ y=z 5x-y+z=18 2x+5y+3z= -1 (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=-1,Z+X=-1. 解下列方程组3x-y+z=3,2x+y-3z=11,x+y+z=123x-y+z=32x+y-3z=11x+y+z=12 3x-2y+2z=3,2x+y-3z=11,x+y+z=12 3x-y+2z=3 2x+y-3z=11 x+y+z=12 x+2y+3z=10,4x+3y+2z=15则x+y+z=