\[ \left \{x'(t)=-5 x(t)-2 y(t),y'(t)=x(t)-7 y(t)\right \} \] ✓ Mathematica : cpu = 0.0089104 (sec), leaf count = 59
\[\left \{\left \{x(t)\to c_1 e^{-6 t} (\sin (t)+\cos (t))-2 c_2 e^{-6 t} \sin (t),y(t)\to c_1 e^{-6 t} \sin (t)+c_2 e^{-6 t} (\cos (t)-\sin (t))\right \}\right \}\] ✓ Maple : cpu = 0.046 (sec), leaf count = 44
\[\left \{x \relax (t ) = {\mathrm e}^{-6 t} \left (c_{1} \sin \relax (t )+c_{2} \cos \relax (t )\right ), y \relax (t ) = -\frac {{\mathrm e}^{-6 t} \left (\left (c_{1}-c_{2}\right ) \cos \relax (t )-\sin \relax (t ) \left (c_{1}+c_{2}\right )\right )}{2}\right \}\]