Question 39
Find all functions $f: \mathbb{R} \rightarrow \mathbb{R}$ such that for all real numbers $x \neq 0$,
$$
f(x)+2 f\left(\frac{x-1}{x}\right)=3 x .
$$
(Note that the function must be defined for all $x \in \mathbb{R}$, including $x=0$.)
$$
f(x)+2 f\left(\frac{x-1}{x}\right)=3 x .
$$
(Note that the function must be defined for all $x \in \mathbb{R}$, including $x=0$.)