Find the general solution of the system
\begin{aligned}&x^{\prime}=-4 x-y, \\&y^{\prime}=x-2 y .\quad\quad\quad\quad\quad (7)\end{aligned}Find the general solution of the system
\begin{aligned}&x^{\prime}=-4 x-y, \\&y^{\prime}=x-2 y .\quad\quad\quad\quad\quad (7)\end{aligned}