已知3x-2y-5z=0,x+2y-7z=0,xyz≠0,求（x^2-2y^2+z^2)/yz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4x-3y+z=0,x+2y-8z=0,xyz不等于0,求x+y-z/x-y+2z的值 x*x+y*y+2z*z-2x+4y+4z+7=0,求xyz的值 设X+Y+Z=0求X^3+X^2Z-XYZ+Y^2Z+Y^3的值 已知3x-2y-5z=0,x+2y+-7y=0 且xyz 不等于0求(x*x-2y*y+z*z)/yz 已知XYZ满足方程组 X+Y-Z=6 Y+Z-X=2 Z+X-y=0 求X Y Z的值 已知x+y-7z=0 x-2y+5z=0(xyz不等于0）,求x+2y-z/y-2x+12z (x-3y+z)^2+/ 5x-4y+z/=0 且xyz≠0 xy+yz+zx/x^2+y^2+z^2 已知2x-3y+z=0,3x-2y-6z=0且xyz≠0,求(x的平方+y的平方+z的平方）／（xy+yz+xz）的值 已知:2x-3y+z=0,3x-2y=6z,且xyz≠0,求x^2+y^2+z^2/xy+yz+xz的值.PS:不会的别 已知 xyz≠0,且x+3y+z＝0,2x+3y-z=0,求x+2y-7z/3x+5y+z 的值.. 已知方程组{2X-Y+3Z=0,X-3Y+Z=0(XYZ≠0),求3Y分之4X+2Z的值