x /2 =y/ 3= z/ 4 3x-4y+5z=14x、y、z、的值 求求了～

x+y/2=z+x/3=y+z/4 x+y+z=27 x+2y=3x+2z=4y+z 求x:y:z 2x+z=10 x+y-z=4 3x-y-z=0 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) (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, x+y=5 2x+3y-z=9 x-y+z=4 {2x+y=10 {x-y+z=4 {3x-y-z=0 设|x|-|y|+|z|=|x+y+z|,且|x+y|=4,|y+z|=5,|y|=3,求(x-y-z)^2的值 证明 ：x/(y+z)+y/(z+x)+z/(x+y)>=3/2其中 x,y,z>0 x/2=y/3=z/4,则x+2y-z/z=? (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 x/2=y/3=z/5 x+3y-z/x-3y+z 若x+y+z=3y=2z,则x/x+y+z=? (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian 3x-y+z=4,2z+3y-z=12,x+y+z=6的解 解方程：{2x+3y+z=7,x+y+z=4,3x+y-z=-4{2x+3y+z=7,x+y+z=4,3x+y-z=-4要过程