已知x+y+z=7,1/(x-1)+1/(y-2)+1/(z-3)=0求(x-1)^2+(y-2)^2+(z-3)^2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满足2X-Y+4Z=8(1);X-2Y-Z=7(2)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 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(Y+Z)分之X+(Z+X)分之Y+(X+Y)分之Z=1,则(Y+Z)分之X平方+(Z+X)分之Y平方+(X+Y)分之Z平方的值为（ ） 已知x:y:z=4:5:7,求:(1)2x+3y+z/5z; (2)x+y/y+z. 已知x,y,z>0,xyz(x+y+z)=1,求证（x+y）(x+z)>=2 已知5x+3y+1/3z=100 7x+y+z=100 那么x+y=? 已知x/3=y/4=z/7,求:（1）x:y；（2）x:y:z 已知x/3=y/4=z/7,求(1)x:y(2)x:y:z. 一条分式数学题已知x y z满足x/x+y + y/z+x + z/x+y =1,求x²/x+y + y²/z+x + z²/x+y的值.3Q 已知方程组{X+Y-7Z=0(1)3X-2Y-Z=0(2)且Z不等于0求X:Y:Z 已知x+2y-3z=0,5x-6y+7z=1;则x:y:z=?把“5z-6y+7z=1”改成“5x-6y+7z=0” 已知x,y,z满足 -------------- + --------------- + ------------- = 1 y+z x+z x+yx•x y•y z•z求 ------------ + ------------ + -------------- = y+z x+z x+y 帮忙解道题 ,已知x+1/y=y+1/z=z+1/x ,证明x+y+z=1 已知；根号x+根号y-1+根号z-2=1/2(x+y+z),求x、y、z 已知{x：y：z=1：2：3,x+y+z=12,求x、y、z的值