(x-3y+z)^2+/ 5x-4y+z/=0 且xyz≠0 xy+yz+zx/x^2+y^2+z^2(x-3y+z)^2+/ 5x-4y+z/=0 且xyz≠0 求：xy+yz+zx/x^2+y^2+z^2

(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 (4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊 2(x+y-z)-3(x-y+z)-5(x+y-z)+6(x-y+z) 计算 化简-(-3x-y+2z)-{-x+【4x-(x-y-z)-3x+2z} x/2=y/3=z/5 x+3y-z/x-3y+z x+2y=3x+2z=4y+z 求x:y:z x+y/2=z+x/3=y+z/4 x+y+z=27 数学--整式运算4(x-y+z)-2(x+y-z)-3(-x-y-z) x+y=5 2x+3y-z=9 x-y+z=4 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. 求化简(x+3y+2z)(x-3y+6z)(x+3y+4z-2z)(x-3y+4z+2z) 5x+y-2z 4 x+2y-3z 2x-3y+5z三元一次方程组 3x-2y+z=4 x+y-z=5 4x-4y+3z=27 ｛ 5x-3y+z=25x+2y-4z=3-5x+y-z=2 x+y+z=4 2x-y+z=3 3x-2y-3z=-5 x:y:z=3:4:5 2x-3y+2z=8 x-y-2z=?