x+2y=3,y+2z=4,z+2x=5请写明过程。。。。。。

(4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=? x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 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) 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 设|x|-|y|+|z|=|x+y+z|,且|x+y|=4,|y+z|=5,|y|=3,求(x-y-z)^2的值 (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. x+y=5 2x+3y-z=9 x-y+z=4 2x+z=10 x+y-z=4 3x-y-z=0 x=y/z=z/3,x+y+z ＝12,求2x+3y+4z是多少, 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. x:y:z=3:4:5 2x-3y+2z=8 x-y-2z=? ｛ 5x-3y+z=25x+2y-4z=3-5x+y-z=2 3x-y+2z=-1 4x+y+z=5 x-2y-z=-2 x+y+z=4 2x-y+z=3 3x-2y-3z=-5 x-y+z=-1 5x+2y-z=6 4x-3y+2z=-5