\[ -a y(x)+(b-x) y'(x)+x y''(x)=0 \] ✓ Mathematica : cpu = 0.0126111 (sec), leaf count = 24
\[\{\{y(x)\to c_1 U(a,b,x)+c_2 L_{-a}^{b-1}(x)\}\}\] ✓ Maple : cpu = 0.061 (sec), leaf count = 17
\[y \relax (x ) = c_{1} \KummerM \left (a , b , x\right )+c_{2} \KummerU \left (a , b , x\right )\]