\[ a y'(x)+b y(x)+y''(x)=0 \] ✓ Mathematica : cpu = 0.004556 (sec), leaf count = 58
\[\left \{\left \{y(x)\to c_1 e^{\frac {1}{2} x \left (-\sqrt {a^2-4 b}-a\right )}+c_2 e^{\frac {1}{2} x \left (\sqrt {a^2-4 b}-a\right )}\right \}\right \}\] ✓ Maple : cpu = 0.01 (sec), leaf count = 41
\[y \relax (x ) = c_{1} {\mathrm e}^{-\frac {\left (a -\sqrt {a^{2}-4 b}\right ) x}{2}}+c_{2} {\mathrm e}^{-\frac {\left (a +\sqrt {a^{2}-4 b}\right ) x}{2}}\]