.已知xyz≠0,且3x+2y-7z=0,7x+4y-15z=0,求 :4x^2-5y^2-6z^2/x^2+2y^2+

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xyz不等于0,且x+2y-z=0,7x-y-z=0,求x+y+z/2x-y-z的值. x*x+y*y+2z*z-2x+4y+4z+7=0,求xyz的值 已知x+y-7z=0 x-2y+5z=0(xyz不等于0）,求x+2y-z/y-2x+12z 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xyz不等于0,且x/3=y/4=z/5,求【2x-3(2y-z)】/x+y+z 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 已知一方程组：x-3y+7z=0与x-2y+4z=0(xyz≠0）,求x:y:z. 已知有理数x.y.z满足（x-z-2)^2+(3x-6y-7)^2=/3y+3z-4/=0求xyz=多少 1.已知 x-3y+7z=0,x-2y+4z=0.(xyz≠0),求 x:y:z