已知 xyz≠0,且x+3y+z＝0,2x+3y-z=0,求x+2y-7z/3x+5y+z 的值..

已知 xyz≠0,且x+3y+z＝0,2x+3y-z=0,求x+2y-7z/3x+5y+z 的值.. 已知4x-3y+z=0,x+2y-8z=0,xyz不等于0,求x+y-z/x-y+2z的值 已知xyz≠0,且x＋3y＋z＝0,2x＋3y－z＝0 ,求x＋2y－7z /3x＋5y＋z的值? 已知xyz不等于0,且x+2y-z=0,7x-y-z=0,求x+y+z/2x-y-z的值. 已知：(x+y-z)/z=(x-y+z)/y+(y+z-x)/x,且xyz≠0,求代数式[(x+y)(y+z)(x+z) 已知x+y-z/z=x-y+z/y=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz 设X+Y+Z=0求X^3+X^2Z-XYZ+Y^2Z+Y^3的值 已知2X+5Y+4Z=0,3X+Y-7Z=0,且XYZ不等于0,求（X+Y+Z）/(2X-3Y+4Z)的值 已知4x-3y-6z=0,x+2y-7z=0,且x,y,z≠0,求2x+3y+6z/x+5y+5z的值. 若4x-3y-6z=0,x+2y-7z=0且xyz≠0； 求(2x+3y+6z)/(x+5y+7z)的值? 已知方程组4x-y+3z=0 2x+y+6z=0且xyz不等于0,则x/y+y/z+z/x是多少 若xyz不等于0,且满足(y+z)/x=(x+z)/y=(x+y)/z,求（y+z)（x+z)（x+y)/xyz的值