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+z=0,x+2y-8z=0,xyz不等于0,求x+y-z/x-y+2z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=-x+y+z/x,且xyz不等于0,求分式[(x+y)(x+z)(y+z)]/xyz 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 已知x/2=y/3=z/4,且x+y+z不等于0,求2x+3y-4z/x+y+z的值 已知xyz不等于0,且x/3=y/4=z/5,求【2x-3(2y-z)】/x+y+z 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 若xyz不等于0,且(y+z)/x=(z+x)/y=(x+y)/z,求(y+z)(z+x)(x+y)/xyz的值? 已知:(x+y)/z=(x+z)/y=(z+y)/x,且xyz不等于0,则分式(x+y)(x+z)(z+x)/xyz的值 已知{4x-5y 2z=0/x 4y-3x=0(xyz不等于0）,求x:y:z:d的值 已知x+y-7z=0 x-2y+5z=0(xyz不等于0）,求x+2y-z/y-2x+12z