\[
\boxed{
 \left( 2\,x+1 \right) ^{2}{\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left( x \right) -2\, \left( 2\,x+1 \right) {\frac {\rm d}{{\rm d}x}}y \left( x \right) -12\,y \left( x \right) -3\,x-1=0}
\]