x+y=18,y+z=13,z+x=14 求xyz的值

(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 x(x+y+z)=6 y(x+y+z)=12 z(x+y+z)=18 解方程组{x(x+y+z)=6,y(x+y+z)=12,z(x+y+z)=18 x+y+z=14 7z=x+y+2 x+z=y x-4y+z=-302x+y-z=18x--y-z=7 14x+4y+z=200,x+y+z=100求解x,y,z x+y=18,y+z=13,z+x=14 求xyz的值 z+=x>y?++x: 方程组 (1) x+2y-3z=12 x-3y+2z= - 13 x-y-z=0 (2) x+ y=z 5x-y+z=18 2x+5y+3z= -1 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