\[ x^2 y''(x)-12 y(x)=0 \] ✓ Mathematica : cpu = 0.0184177 (sec), leaf count = 18
\[\left \{\left \{y(x)\to \frac {c_1 x^7+c_2}{x^3}\right \}\right \}\]
✓ Maple : cpu = 0.008 (sec), leaf count = 15
\[ \left \{ y \left ( x \right ) ={\frac {{\it \_C1}\,{x}^{7}+{\it \_C2}}{{x}^{3}}} \right \} \]