\[
\boxed{
{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) =-{\frac { \left( {x}^{2}a \left( 1-a \right) -b \left( x+b \right)  \right) y \left( x \right) }{{x}^{4}}}=0}
\]