Consider the following joint probability density function of the random variables $X$ and $Y:$
$$
f\{x, y)=\left\{\begin{array}{ll}
\frac{3 x-y}{9}, & 1 < x < 3,1< y<2, \\
0, & \text { elsewhere. }
\end{array}\right.
$$
(a) Find the marginal density functions of $X$ and $Y$.
(b) Are $X$ and $Y$ independent?
(c) Find $P(X>2)$.