\[ \left \{x'(t)+3 x(t)+4 y(t)=0,2 x(t)+y'(t)+5 y(t)=0\right \} \] ✓ Mathematica : cpu = 0.0122483 (sec), leaf count = 72
\[\left \{\left \{x(t)\to \frac {1}{3} e^{-7 t} \left (c_1 \left (2 e^{6 t}+1\right )-2 c_2 \left (e^{6 t}-1\right )\right ),y(t)\to \frac {1}{3} e^{-7 t} \left (c_2 \left (e^{6 t}+2\right )-c_1 \left (e^{6 t}-1\right )\right )\right \}\right \}\]
✓ Maple : cpu = 0.04 (sec), leaf count = 35
\[ \left \{ \left \{ x \left ( t \right ) ={\it \_C1}\,{{\rm e}^{-7\,t}}+{\it \_C2}\,{{\rm e}^{-t}},y \left ( t \right ) ={\it \_C1}\,{{\rm e}^{-7\,t}}-{\frac {{\it \_C2}\,{{\rm e}^{-t}}}{2}} \right \} \right \} \]