\[ \left \{x'(t)+3 x(t)-y(t)=e^{2 t},x(t)+y'(t)+5 y(t)=e^t\right \} \] ✓ Mathematica : cpu = 0.0779975 (sec), leaf count = 162
\[\left \{\left \{x(t)\to -e^t (t+1) \left (\frac {t}{5}+\frac {1}{36} e^t (6 t-7)-\frac {1}{25}\right )+e^t t \left (\frac {t}{5}+\frac {1}{36} e^t (6 t-1)+\frac {4}{25}\right )+c_1 e^{-4 t} (t+1)+c_2 e^{-4 t} t,y(t)\to e^t t \left (\frac {t}{5}+\frac {1}{36} e^t (6 t-7)-\frac {1}{25}\right )-e^t (t-1) \left (\frac {t}{5}+\frac {1}{36} e^t (6 t-1)+\frac {4}{25}\right )-c_1 e^{-4 t} t-c_2 e^{-4 t} (t-1)\right \}\right \}\] ✓ Maple : cpu = 0.083 (sec), leaf count = 64
\[\left \{x \relax (t ) = {\mathrm e}^{-4 t} c_{2}+{\mathrm e}^{-4 t} t c_{1}+\frac {{\mathrm e}^{t}}{25}+\frac {7 \,{\mathrm e}^{2 t}}{36}, y \relax (t ) = -\frac {{\mathrm e}^{2 t}}{36}-{\mathrm e}^{-4 t} c_{2}-{\mathrm e}^{-4 t} t c_{1}+{\mathrm e}^{-4 t} c_{1}+\frac {4 \,{\mathrm e}^{t}}{25}\right \}\]