Solve in the real numbers $x, y, z$ a system of the equations:
\[
\begin{cases}
x^2 - (y+z+yz)x + (y+z)yz = 0  \\ 
y^2 - (z + x + zx)y + (z+x)zx = 0 \\
  z^2 - (x+y+xy)z + (x+y)xy = 0. \\
\end{cases}
\]