已知3x-2y-5z=0,2x-5y+4z=0,且x.y.z均不为0,求3x^2+2y^2+5z^2/5x^2+y^2-9z^2的值

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-5y+2z=0 3x-5y-4z=0,求x：y:z 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4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z 已知x+4y+3z=3x-2y-5z=0,求x+2y-z/2x-3y+7z的值 已知3x+4y+5z=0,2x+3y-4z=0,求(x+y+z)/(x-y+z) 已知2x+3y-4z=0,3x+4y+5z=0,求x+y+z/（除以）x-y+z的值. 已知{3x+4y+5z=0,2x+3y-4z=0,求x+y+z/x-y+z的值. 已知2x+3y-4z=0,3x+4y-5z=0.求x+y+z除以x-y+z, 已知2x+3y-4z=0,3x+3y+5z=0,求x+y+x/x-y+z的值 已知x,y,z满足方程组：4x-5y+2z=o;x+4y-3x=0,求x:y:z的值 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)/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=? 已知x+2y/3=y+3z/4=z+5x/5,则x:y:z=