已知｛2x-5y=0 则x+y+z/2y= x-6y+3z=0

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^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+4y-3z=0,4x-5y+2z=0,则x：y：z 已知方程组4x-5y+2z=0 x+2y=3z 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-y+z=0,3x+y-5z=0,则x+y+z/x+2y-3z=? 已知x-y+z=0.3x+y-5z=0,则x+y+z/x+2y-3z=_______ 已知xyz不等于0,且{x+3y+5z=0 x2+3y+z=0,则x.x+y.y-2z.2z/3x.3x+2y.2y+z.z=? 已知x+4y-3z=0；4x-5y+2z=0,则3y-5z分之2x-y+3z=? 已知{x+4y-3z=0,4x-5y+2z=0,则2x-y+3z分之3y-5z=? 已知x+2y-7z=0,3x-5y+z=0,用z的代数式分别表示x,y,则y= x= 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-5y+2z=0 3x-5y-4z=0,求x：y:z 已知{x-3y+2z=0 3x-3y-4z+0,则x:y:z=? 已知(x+2y)/3=(y+3z)/4=(z+5x)/5,则x:y:z= 已知x+2y/3=y+3z/4=z+5x/5,则x:y:z=?