\[
\boxed{
x{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) + \left(  \left( a+b \right) x+m+n \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) + \left( abx+na+bm \right) y \left( x \right) =0}
\]