[_Laguerre]
Book solution method
TO DO
Mathematica ✓
cpu = 0.0869933 (sec), leaf count = 21
Maple ✓
cpu = 0.093 (sec), leaf count = 21
DSolve[n*y[x] + (1 - x)*y'[x] + x*y''[x] == 0,y[x],x]
Mathematica raw output
{{y[x] -> C[1]*HypergeometricU[-n, 1, x] + C[2]*LaguerreL[n, x]}}
Maple raw input
dsolve(x*diff(diff(y(x),x),x)+(1-x)*diff(y(x),x)+n*y(x) = 0, y(x),'implicit')
Maple raw output
y(x) = _C1*KummerM(-n,1,x)+_C2*KummerU(-n,1,x)