\[ \left \{x'(t)=\text {a1} x(t)+\text {b1} y(t)+\text {c1},y'(t)=\text {a2} x(t)+\text {b2} y(t)+\text {c2}\right \} \] ✓ Mathematica : cpu = 0.735832 (sec), leaf count = 2062
DSolve[{Derivative[1][x][t] == c1 + a1*x[t] + b1*y[t], Derivative[1][y][t] == c2 + a2*x[t] + b2*y[t]},{x[t], y[t]},t]
\[\left \{\left \{x(t)\to -\frac {\text {b1} e^{-\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \left (\frac {2 \left (\left (\text {a1}-\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) \text {c2}-2 \text {a2} \text {c1}\right ) e^{\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} t}}{-\text {a1}-\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}-\frac {2 \left (2 \text {a2} \text {c1}+\left (-\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) \text {c2}\right )}{\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}\right ) \left (e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}-e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}\right )}{2 \left (\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}\right )}-\frac {\text {b1} c_2 \left (e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}-e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}\right )}{\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}+\frac {e^{-\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \left (\frac {2 \left (-\text {a1} \text {c1}+\text {b2} \text {c1}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} \text {c1}-2 \text {b1} \text {c2}\right ) e^{\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} t}}{-\text {a1}-\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}-\frac {2 \left (\text {a1} \text {c1}-\text {b2} \text {c1}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} \text {c1}+2 \text {b1} \text {c2}\right )}{\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}\right ) \left (-e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \text {a1}+e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \text {a1}+\text {b2} e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}-\text {b2} e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}\right )}{4 \left (\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}\right )}+\frac {\left (-e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \text {a1}+e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \text {a1}+\text {b2} e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}-\text {b2} e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}\right ) c_1}{2 \sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}},y(t)\to -\frac {\text {a2} e^{-\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \left (\frac {2 \left (-\text {a1} \text {c1}+\text {b2} \text {c1}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} \text {c1}-2 \text {b1} \text {c2}\right ) e^{\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} t}}{-\text {a1}-\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}-\frac {2 \left (\text {a1} \text {c1}-\text {b2} \text {c1}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} \text {c1}+2 \text {b1} \text {c2}\right )}{\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}\right ) \left (e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}-e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}\right )}{2 \left (\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}\right )}-\frac {\text {a2} c_1 \left (e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}-e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}\right )}{\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}+\frac {e^{-\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \left (\frac {2 \left (\left (\text {a1}-\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) \text {c2}-2 \text {a2} \text {c1}\right ) e^{\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} t}}{-\text {a1}-\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}-\frac {2 \left (2 \text {a2} \text {c1}+\left (-\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) \text {c2}\right )}{\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}\right ) \left (e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \text {a1}-e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \text {a1}-\text {b2} e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\text {b2} e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}\right )}{4 \left (\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}\right )}+\frac {\left (e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \text {a1}-e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t} \text {a1}-\text {b2} e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} e^{\frac {1}{2} \left (\text {a1}+\text {b2}-\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\text {b2} e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}} e^{\frac {1}{2} \left (\text {a1}+\text {b2}+\sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}\right ) t}\right ) c_2}{2 \sqrt {\text {a1}^2-2 \text {b2} \text {a1}+\text {b2}^2+4 \text {a2} \text {b1}}}\right \}\right \}\] ✓ Maple : cpu = 0.109 (sec), leaf count = 224
dsolve({diff(x(t),t) = a1*x(t)+b1*y(t)+c1, diff(y(t),t) = a2*x(t)+b2*y(t)+c2})
\[\left \{x \left (t \right ) = {\mathrm e}^{\frac {\left (\mathit {a1} +\mathit {b2} +\sqrt {\mathit {a1}^{2}-2 \mathit {a1} \mathit {b2} +4 \mathit {b1} \mathit {a2} +\mathit {b2}^{2}}\right ) t}{2}} c_{2}+{\mathrm e}^{\frac {\left (\mathit {a1} +\mathit {b2} -\sqrt {\mathit {a1}^{2}-2 \mathit {a1} \mathit {b2} +4 \mathit {b1} \mathit {a2} +\mathit {b2}^{2}}\right ) t}{2}} c_{1}+\frac {\mathit {c2} \mathit {b1} -\mathit {b2} \mathit {c1}}{\mathit {a1} \mathit {b2} -\mathit {b1} \mathit {a2}}, y \left (t \right ) = \frac {-c_{1} \left (\mathit {a1} \mathit {b2} -\mathit {b1} \mathit {a2} \right ) \left (\sqrt {\mathit {a1}^{2}-2 \mathit {a1} \mathit {b2} +4 \mathit {b1} \mathit {a2} +\mathit {b2}^{2}}+\mathit {a1} -\mathit {b2} \right ) {\mathrm e}^{\frac {\left (\mathit {a1} +\mathit {b2} -\sqrt {\mathit {a1}^{2}-2 \mathit {a1} \mathit {b2} +4 \mathit {b1} \mathit {a2} +\mathit {b2}^{2}}\right ) t}{2}}+c_{2} \left (\mathit {a1} \mathit {b2} -\mathit {b1} \mathit {a2} \right ) \left (\sqrt {\mathit {a1}^{2}-2 \mathit {a1} \mathit {b2} +4 \mathit {b1} \mathit {a2} +\mathit {b2}^{2}}-\mathit {a1} +\mathit {b2} \right ) {\mathrm e}^{\frac {\left (\mathit {a1} +\mathit {b2} +\sqrt {\mathit {a1}^{2}-2 \mathit {a1} \mathit {b2} +4 \mathit {b1} \mathit {a2} +\mathit {b2}^{2}}\right ) t}{2}}-2 \mathit {b1} \left (\mathit {a1} \mathit {c2} -\mathit {a2} \mathit {c1} \right )}{2 \mathit {b1} \left (\mathit {a1} \mathit {b2} -\mathit {b1} \mathit {a2} \right )}\right \}\]