\[ (2 x+1)^2 y''(x)-2 (2 x+1) y'(x)-12 y(x)-3 x-1=0 \] ✓ Mathematica : cpu = 0.0463017 (sec), leaf count = 41
\[\left \{\left \{y(x)\to \frac {192 c_1 (2 x+1)^4+192 c_2-72 x^2-56 x-7}{192 (2 x+1)}\right \}\right \}\]
✓ Maple : cpu = 0.023 (sec), leaf count = 41
\[ \left \{ y \left ( x \right ) ={\frac {{\it \_C1}}{2\,x+1}}+ \left ( 2\,x+1 \right ) ^{3}{\it \_C2}+{\frac {-72\,{x}^{2}-56\,x-7}{384\,x+192}} \right \} \]