9.2. Let $x$, $y$, and $z$ be non-zero real numbers satisfying the equations: $\frac{x+y}{z}=\frac{y+z}{x}=\frac{z+x}{y}$. Find all possible values of the expression $\frac{(x+y)(y+z)(z+x)}{x y z}$. Justify that there can be no other values.