\[ \left \{x'(t)=-y(t),y'(t)=2 x(t)+2 y(t)\right \} \] ✓ Mathematica : cpu = 0.0110795 (sec), leaf count = 52
DSolve[{Derivative[1][x][t] == -y[t], Derivative[1][y][t] == 2*x[t] + 2*y[t]},{x[t], y[t]},t]
\[\left \{\left \{x(t)\to c_1 e^t (\cos (t)-\sin (t))-c_2 e^t \sin (t),y(t)\to 2 c_1 e^t \sin (t)+c_2 e^t (\sin (t)+\cos (t))\right \}\right \}\] ✓ Maple : cpu = 0.045 (sec), leaf count = 39
dsolve({diff(x(t),t) = -y(t), diff(y(t),t) = 2*x(t)+2*y(t)})
\[\{x \left (t \right ) = {\mathrm e}^{t} \left (c_{1} \sin \left (t \right )+c_{2} \cos \left (t \right )\right ), y \left (t \right ) = -\left (\left (c_{1}+c_{2}\right ) \cos \left (t \right )+\sin \left (t \right ) \left (c_{1}-c_{2}\right )\right ) {\mathrm e}^{t}\}\]