\[ \boxed { x{\it d4y} \left ( x \right ) +5\,{\frac {{\rm d}^{3}}{{\rm d}{x}^{3}}}y \left ( x \right ) -24=0} \]
Mathematica: cpu = 0.012002 (sec), leaf count = 34 \[ \left \{\left \{y(x)\to c_4 x^2-\frac {c_1}{24 x^2}+c_3 x+c_2+\frac {4 x^3}{5}\right \}\right \} \]
Maple: cpu = 0.047 (sec), leaf count = 26 \[ \left \{ y \left ( x \right ) =-{\frac {{\it \_C1}}{24\,{x}^{2}}}+{ \frac {4\,{x}^{3}}{5}}+{\frac {{\it \_C2}\,{x}^{2}}{2}}+{\it \_C3}\,x+ {\it \_C4} \right \} \]