\[
\boxed{
{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) ={\frac { \left( a+b \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) }{{x}^{2}}}-{\frac { \left(  \left( a+b \right) x+ab \right) y \left( x \right) }{{x}^{4}}}=0}
\]