x+y=13,y+Z=14,x+z=9,求答案,给好评

(x+y-z)(x-y+z)= fangchengzu:X+Z=Y 7Z=X+Y+Z X+Y+Z=14 X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) 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)=? (y+z)/x=(z+x)/y=(x+y)/z求x+y-z/x+y+z的值 解方程组：{x(x+y+z)=6 {y(x+y+z)=9 {z(x+y+z)=10 x+y+z=14 7z=x+y+2 x+z=y 14x+4y+z=200,x+y+z=100求解x,y,z X+Y=9X+Z=13Y+Z=14 方程组{x+y=9,y+z=14,x+z=13 x+y=13,y+Z=14,x+z=9,求答案,给好评 z+=x>y?++x: X ,Y,Z各代表一个数,且满足以下三个等式X+X+Y+Z=17X+Y+Y+Z=14X+Y+Z+Z=13求X,Y,Z的值 用行列式的性质证明：y+z z+x x+y x y z x+y y+z z+x =2 z x y z+x x+y y+z y z x 这个怎么证? x=y; y=z; z=x/y x+y+z=6 x+2y+3z=14 y+1=z 已知x-y/x+y=y+z/2(y-z)=z+x/3(z-x),求证8x+9y+5z=0THX..