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