x+y+z=14 7z=x+y+2 x+z=y

(x+y-z)(x-y+z)= X+Y+Z=? 试证明(x+y-2z)+(y+z-2x)+(z+x-2y)=3(x+y-2z)(y+z-2x)(z+x-2y) (x+y-z)^2-(x-y+z)^2=? x+2y+3z=14 2x+y+z=7 3x+y+2z=11 x+z=y 7*x=y+z+2 x+y+z=14 解这个方程组、 f(x,y,z,w)=x*(x+y)*(x+y+z)*(x+y+z+w) 分解因式:f(x,y,z)=x^2(y-z)+y^2(z-x)+z^2(x-y) x,y,z为实数 且(y-z)^2+(x-y)^2+(z-x)^2=(y+z-2x)^2+(x+z-2y)^2+(x+y x,y,z为实数且(y-z)平方+(x-y)平方+(z-x)平方=(y+z-2x)平方+(z+x-2y)平方+(x+y- x+2y+3z=14 2x+y+z=7 3x+y+2z=11 求x y z x/2=y/3=z/5 x+3y-z/x-3y+z