2.3*x+2.7*y+2.9*z=30 求X Y Z (是整数) 急

2.3*x+2.7*y+2.9*z=30 求X Y Z (是整数) 急 (x+y-z)(x-y+z)= X+Y+Z=? x/y=(x+z)/(y+z)y/z=(x+y)/(x+z) x+y+z=30 120x=600z 100y=400z 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 6x+5y+3z=100 x+y+z=30 求 x y 已知x+y=27,y+z=33,x+z=30,则x+y+z=? x-y=1.85 z-y=2.7 x+y+z=19.55 怎么解 fangchengzu:X+Z=Y 7Z=X+Y+Z X+Y+Z=14 z+=x>y?++x: 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-2y+z)(x+y-2z)分之（y-x)(z-x) + (x+y-2z)(y+z-2x)分之(z-y)(x-y) + (y+z-2z)(x-2y+z)分之（x-z)(y-z)=?第三部分那个是 （y+z-2x)(x-2y+z)分之（x-z)(y-z) z=x^(y/z) 偏导数 x=2y z-x=30 x+y+z=180 已知(x+y)(x+z)=x,(y+z)(y+x)=2y,(z+x)(z+y)=3z,求x,y,z