\[ \left \{x'(t)=y(t)-z(t),y'(t)=x(t)+y(t),z'(t)=x(t)+z(t)\right \} \] ✓ Mathematica : cpu = 0.0112027 (sec), leaf count = 93
\[\left \{\left \{x(t)\to \left (c_2-c_3\right ) \left (e^t-1\right )+c_1,y(t)\to c_1 \left (e^t-1\right )+c_2 \left (e^t t+1\right )-c_3 \left (e^t (t-1)+1\right ),z(t)\to c_1 \left (e^t-1\right )+c_2 \left (e^t (t-1)+1\right )-c_3 \left (e^t (t-2)+1\right )\right \}\right \}\]
✓ Maple : cpu = 0.072 (sec), leaf count = 43
\[ \left \{ \left \{ x \left ( t \right ) ={\it \_C2}+{\it \_C3}\,{{\rm e}^{t}},y \left ( t \right ) = \left ( {\it \_C3}\,t+{\it \_C1} \right ) {{\rm e}^{t}}-{\it \_C2},z \left ( t \right ) = \left ( \left ( t-1 \right ) {\it \_C3}+{\it \_C1} \right ) {{\rm e}^{t}}-{\it \_C2} \right \} \right \} \]