\[ \left \{4 x'(t)+2 x(t)+9 y'(t)+31 y(t)=e^t,3 x'(t)+x(t)+7 y'(t)+24 y(t)=3\right \} \] ✓ Mathematica : cpu = 0.307059 (sec), leaf count = 180
\[\left \{\left \{x(t)\to \frac {1}{442} \left (3 \left (153 e^t-754\right ) \sin (t)+31 \left (17 e^t-78\right ) \cos (t)\right ) (\cos (t)-\sin (t))+\frac {1}{221} \sin (t) \left (\left (493 e^t-2340\right ) \sin (t)+\left (34 e^t-78\right ) \cos (t)\right )-c_2 e^{-4 t} \sin (t)+c_1 e^{-4 t} (\cos (t)-\sin (t)),y(t)\to \frac {1}{221} \sin (t) \left (3 \left (153 e^t-754\right ) \sin (t)+31 \left (17 e^t-78\right ) \cos (t)\right )-\frac {1}{221} (\sin (t)+\cos (t)) \left (\left (493 e^t-2340\right ) \sin (t)+\left (34 e^t-78\right ) \cos (t)\right )+2 c_1 e^{-4 t} \sin (t)+c_2 e^{-4 t} (\sin (t)+\cos (t))\right \}\right \}\] ✓ Maple : cpu = 0.101 (sec), leaf count = 62
\[ \left \{ \left \{ x \left ( t \right ) ={{\rm e}^{-4\,t}}\sin \left ( t \right ) {\it \_C2}+{{\rm e}^{-4\,t}}\cos \left ( t \right ) {\it \_C1}-{\frac {93}{17}}+{\frac {31\,{{\rm e}^{t}}}{26}},y \left ( t \right ) ={\frac { \left ( \left ( -221\,{\it \_C1}-221\,{\it \_C2} \right ) \cos \left ( t \right ) +221\,\sin \left ( t \right ) \left ( {\it \_C1}-{\it \_C2} \right ) \right ) {{\rm e}^{-4\,t}}}{221}}-{\frac {2\,{{\rm e}^{t}}}{13}}+{\frac {6}{17}} \right \} \right \} \]