\[ \left \{x'(t)=a x(t),y'(t)=b\right \} \] ✓ Mathematica : cpu = 0.0162797 (sec), leaf count = 22
DSolve[{Derivative[1][x][t] == a*x[t], Derivative[1][y][t] == b},{x[t], y[t]},t]
\[\left \{\left \{x(t)\to c_1 e^{a t},y(t)\to b t+c_2\right \}\right \}\] ✓ Maple : cpu = 0.051 (sec), leaf count = 19
dsolve({diff(x(t),t) = a*x(t), diff(y(t),t) = b})
\[\{x \left (t \right ) = c_{1} {\mathrm e}^{a t}, y \left (t \right ) = b t +c_{2}\}\]