已知x/7=y/5=z/1,求x^2:yz的值

已知 x/(y+z)+y/(z+x)+z/(x+y)=1求 (x*x)/(y+z)+(y*y)/(x+z)+(z*z)/(x+y)=? 已知x:y:z=4:5:7,求:(1)2x+3y+z/5z; (2)x+y/y+z. 已知2x+5y+4z=6 3x+y-7z=-4求x+y-z 已知x:y:z=1:3:5,求（2x+3y-z)/(x+y-2z)的值 已知x:：y：z=3：4：5,(1)求x+y分之z的值；（2）若x+y+z=6,求x,y,z. 1、已知x/y=7/2,求x/x+y 2、已知x/2=y/3=z/4,求x+y+z/2x+3y-z!1、已知x/y=7/2,求x/x+y2、已知x/2=y/3=z/4,求x+y+z/2x+3y-z! 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,求x+y+z的值 已知实数x y z满足x/(x+1)=y/(y+2)=z/(z+3)=(x+y+z)/3,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 已知x+4y+3z=3x-2y-5z=0,求x+2y-z/2x-3y+7z的值 已知4x-3y-6z=0,x+2y-7z=0,求5x+2y-z/2x-3y-10z 已知:x+y+z=0,5x-3y-z=0,求:5x-y+z/2x+8y+7z 的值 已知X、Y、Z满足2X-Y+4Z=8(1);X-2Y-Z=7(2)求X-Y-Z的值 已知x.y.z满足x-2y+z=0且7x+4y-5z=0,求x:y:z的值 已知x、y、z满足x—2y+z=0 7x+4y—5z=0 ,求x：y：z 已知x,y,z满足方程组x-2y+z=0 7x+4y-5z=0求x:y:z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：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.