解2x+5y+3z=15 x-2y+z=-2 3x+y-2z=3

试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) x/2=y/3=z/5 x+3y-z/x-3y+z 解方程组{z=x+y 3x-2y-2z=-5 2x+y-z=3 解方程组 z=x+y 2x-3y+2z=5 x+2y-z=3 解方程组：x+y+z=4,x+y+2z=5,3x+y-z=6 已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3 {x+y+z=1;x+3y+7z=-1;z+5y+8z=-2 x+2y=3 x+y+z=36 2x+y+z=15 2y=3z x-y=1 x+2y+z x-z=-1 2x+z-y=1 x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, 如果|x+y+z-6|+|2x+3y-z-12|+|2x-y-z|=0求x,y, 已知2x+3y+z=130,3x+5y+z=180,试求x+2y/z+y+z【在线等高手解方程】 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai