{上面x/2=y/3=z/5下面2x+y+3z=88,

{上面x/2=y/3=z/5下面2x+y+3z=88, x/2=y/3=z/5 x+3y-z/x-3y+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=1;x+3y+7z=-1;z+5y+8z=-2 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=z/3,x+y+z ＝12,求2x+3y+4z是多少, (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai X+Y=Z 2X-3Y+2Z=5 X+3Y-Z=3 x+y=z 2x-3y+2z=5 x+2y-z=3 解方程组{z=x+y 3x-2y-2z=-5 2x+y-z=3 x+y-z=0 2x-3y+2z=5 x+2y-z=3 解方程组 z=x+y 2x-3y+2z=5 x+2y-z=3