Question 93
Find all functions $f: \mathbb{R} \setminus \{-1\} \to \mathbb{R}$ such that
$$
f(x) + f(y) = (x + y + 2)f(x)f(y)
$$
for all $x, y \in \mathbb{R} \setminus \{-1\}$.
$$
f(x) + f(y) = (x + y + 2)f(x)f(y)
$$
for all $x, y \in \mathbb{R} \setminus \{-1\}$.