\[ \left \{x'(t)=-5 x(t)-2 y(t),y'(t)=x(t)-7 y(t)\right \} \] ✓ Mathematica : cpu = 0.0084302 (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 = 0.037 (sec), leaf count = 44
\[ \left \{ \left \{ x \left ( t \right ) ={{\rm e}^{-6\,t}} \left ( \sin \left ( t \right ) {\it \_C1}+\cos \left ( t \right ) {\it \_C2} \right ) ,y \left ( t \right ) =-{\frac { \left ( \left ( {\it \_C1}-{\it \_C2} \right ) \cos \left ( t \right ) -\sin \left ( t \right ) \left ( {\it \_C1}+{\it \_C2} \right ) \right ) {{\rm e}^{-6\,t}}}{2}} \right \} \right \} \]