\[
\boxed{
 \left\{ {\frac {\rm d}{{\rm d}t}}x \left( t \right) +{\frac {\rm d}{{\rm d}t}}y \left( t \right) -x \left( t \right) +3\,y \left( t \right) ={{\rm e}^{t}}-1,{\frac {\rm d}{{\rm d}t}}x \left( t \right) +{\frac {\rm d}{{\rm d}t}}y \left( t \right) +2\,x \left( t \right) +y \left( t \right) ={{\rm e}^{2\,t}}+t \right\} }
\]