\[ \left \{x'(t)+2 y(t)=3 t,y'(t)-2 x(t)=4\right \} \] ✓ Mathematica : cpu = 0.0355605 (sec), leaf count = 132
\[\left \{\left \{x(t)\to \cos (2 t) \left (\frac {3}{2} t \sin (2 t)-\frac {5}{4} \cos (2 t)\right )-\sin (2 t) \left (\frac {5}{4} \sin (2 t)+\frac {3}{2} t \cos (2 t)\right )+c_1 \cos (2 t)-c_2 \sin (2 t),y(t)\to \cos (2 t) \left (\frac {5}{4} \sin (2 t)+\frac {3}{2} t \cos (2 t)\right )+\sin (2 t) \left (\frac {3}{2} t \sin (2 t)-\frac {5}{4} \cos (2 t)\right )+c_2 \cos (2 t)+c_1 \sin (2 t)\right \}\right \}\] ✓ Maple : cpu = 0.037 (sec), leaf count = 39
\[ \left \{ \left \{ x \left ( t \right ) =\sin \left ( 2\,t \right ) {\it \_C2}+\cos \left ( 2\,t \right ) {\it \_C1}-{\frac {5}{4}},y \left ( t \right ) =-\cos \left ( 2\,t \right ) {\it \_C2}+\sin \left ( 2\,t \right ) {\it \_C1}+{\frac {3\,t}{2}} \right \} \right \} \]