）2x+3y=5 3y-4z=3 4z+5x=7

已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/（除以）x-y+z的值. x+y/2=z+x/3=y+z/4 x+y+z=27 x+2y=3x+2z=4y+z 求x:y:z 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. (4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? 设|x|-|y|+|z|=|x+y+z|,且|x+y|=4,|y+z|=5,|y|=3,求(x-y-z)^2的值 1.已知x:y:z=4:5:7,求：（一）2x+3y+z/5z； （二）x+y/y+z 非常急, (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 x,y,z不是0.3z=4y,z=3x求（x+y）：（x+z）. 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 (x+y):(y+z):(z+x)=3:4:5 3x+y-z=-4已知(x+y):(y+z):(z+x)=3:4:5 ；3x+y-z=-4求x y z 若xyz≠0且4(x/z)-5(y/z)=-2,(x/z)+4(y/z)=3,求x:y:z 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. 2x+z=10 x+y-z=4 3x-y-z=0 3x-2y+z=4 x+y-z=5 4x-4y+3z=27 x+y+z=4 2x-y+z=3 3x-2y-3z=-5 ｛ 5x-3y+z=25x+2y-4z=3-5x+y-z=2