If the system of equations $$\begin{aligned}
& k x + y + 2 z = 1 \\
& 3 x - y - 2 z = 2 \\
& - 2 x - 2 y - 4 z = 3
\end{aligned}$$ has infinitely many solutions, then $k$ is equal to
If the system of equations
$$\begin{aligned}
& k x + y + 2 z = 1 \\
& 3 x - y - 2 z = 2 \\
& - 2 x - 2 y - 4 z = 3
\end{aligned}$$
has infinitely many solutions, then $k$ is equal to