\[ \left \{x'(t)=-y(t),y'(t)=2 x(t)+2 y(t)\right \} \] ✓ Mathematica : cpu = 0.0126009 (sec), leaf count = 52
\[\left \{\left \{x(t)\to c_1 e^t (\cos (t)-\sin (t))-c_2 e^t \sin (t),y(t)\to 2 c_1 e^t \sin (t)+c_2 e^t (\sin (t)+\cos (t))\right \}\right \}\] ✓ Maple : cpu = 0.05 (sec), leaf count = 39
\[\{\{x \left (t \right ) = \left (c_{1} \sin \left (t \right )+c_{2} \cos \left (t \right )\right ) {\mathrm e}^{t}, y \left (t \right ) = -\left (\left (c_{1}+c_{2}\right ) \cos \left (t \right )+\left (c_{1}-c_{2}\right ) \sin \left (t \right )\right ) {\mathrm e}^{t}\}\}\]