\[ (3 a+b x) y'(x)+a x y''(x)+3 b y(x)=0 \] ✓ Mathematica : cpu = 0.126842 (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 = 0.056 (sec), leaf count = 55
\[\left \{y \left (x \right ) = \frac {c_{2} b^{2} x^{2} \Ei \left (1, -\frac {b x}{a}\right ) {\mathrm e}^{-\frac {b x}{a}}+c_{1} x^{2} {\mathrm e}^{-\frac {b x}{a}}+c_{2} \left (b x +a \right ) a}{x^{2}}\right \}\]