\[ a y(x)+(b+x) y'(x)+x y''(x)=0 \] ✓ Mathematica : cpu = 0.0226922 (sec), leaf count = 40
\[\left \{\left \{y(x)\to c_1 e^{-x} U(b-a,b,x)+c_2 e^{-x} L_{a-b}^{b-1}(x)\right \}\right \}\] ✓ Maple : cpu = 0.323 (sec), leaf count = 30
\[ \left \{ y \left ( x \right ) ={{\rm e}^{-x}} \left ( {{\sl U}\left (-a+b,\,b,\,x\right )}{\it \_C2}+{{\sl M}\left (-a+b,\,b,\,x\right )}{\it \_C1} \right ) \right \} \]