\[ y(x) y''(x)-a y'(x)^2=0 \] ✓ Mathematica : cpu = 0.117388 (sec), leaf count = 26
\[\left \{\left \{y(x)\to c_2 (-a x+x-c_1){}^{\frac {1}{1-a}}\right \}\right \}\] ✓ Maple : cpu = 0.912 (sec), leaf count = 25
\[y \relax (x ) = \left (\frac {1}{\left (1-a \right ) \left (c_{1} x +c_{2}\right )}\right )^{\frac {1}{a -1}}\]