\[
\boxed{
 \left\{ {\frac {\rm d}{{\rm d}t}}x \left( t \right) +3\,x \left( t \right) +4\,y \left( t \right) =0,{\frac {\rm d}{{\rm d}t}}y \left( t \right) +2\,x \left( t \right) +5\,y \left( t \right) =0 \right\} }
\]