\[ (3 a+b x) y'(x)+a x y''(x)+3 b y(x)=0 \] ✓ Mathematica : cpu = 0.116849 (sec), leaf count = 79
\[\left \{\left \{y(x)\to c_1 e^{-\frac {b x}{a}}-\frac {c_2 e^{-\frac {b x}{a}} \left (a^2 e^{\frac {b x}{a}}-b^2 x^2 \text {Ei}\left (\frac {b x}{a}\right )+a b x e^{\frac {b x}{a}}\right )}{2 a^2 x^2}\right \}\right \}\] ✓ Maple : cpu = 0.042 (sec), leaf count = 55
\[y \relax (x ) = \frac {\Ei \left (1, -\frac {b x}{a}\right ) {\mathrm e}^{-\frac {b x}{a}} c_{2} b^{2} x^{2}+c_{1} {\mathrm e}^{-\frac {b x}{a}} x^{2}+a c_{2} \left (b x +a \right )}{x^{2}}\]