已知x/3=y=z/2≠0,则2x^2-2y^2+5z^2/xy+yz+zx

已知：x+2y-3z=0,3x-2y+z=0,则x：y：z= 已知2x-y-z=0,3x+4y-2z=0,则x：y：z=? 已知x-2y+3z=0,x-3y+4z=0,则x:y:z= 已知{x-3y+2z=0 3x-3y-4z+0,则x:y:z=? 已知方程组4x-5y+2z=0 x+2y=3z 则x:y:z 已知x+4y-3z=0,4x-5y+2z=0,则x：y：z 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX.. 已知x,y,z 大于0,x+y+z=2,求证 xz/y(y+z)+zy/x(x+y)+yx/z(z+x)大于等于2/3 已知：x^2/(z+y)+y^2/(x+z)+z^2/(x+y)=0,求x/(z+y)+y/(x+z)+z/(x+y)的值. 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z 已知3x-4y-z=0,2x+y-8z=0,且z≠0,则x：y：z=（ ） 已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____. 已知x+2y-4z=0,3x-y-z=0,则3x+2y+z/x+2y+z= 已知x-y+z=0,3x+y-5z=0,则x+y+z/x+2y-3z=? 已知4x-3y-6z=0,x+2y-7z=0,则x-y+z/x+y+z=_________ 已知4x-3y+6z=0 x+2y-7z=0 则x-y+z/x+y-z=? 已知{4x-3y-6z=0、x+2y-7z=0,则x-y+z：x+y+z= 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