\[ y'(x)=\frac {\left (4 a x-y(x)^2\right )^2}{y(x)} \] ✓ Mathematica : cpu = 0.169847 (sec), leaf count = 105
\[\left \{\left \{y(x)\to -\sqrt {4 a x-\sqrt {2} \sqrt {a} \tanh \left (\frac {2 \sqrt {2} a x-\sqrt {2} c_1}{\sqrt {a}}\right )}\right \},\left \{y(x)\to \sqrt {4 a x-\sqrt {2} \sqrt {a} \tanh \left (\frac {2 \sqrt {2} a x-\sqrt {2} c_1}{\sqrt {a}}\right )}\right \}\right \}\] ✓ Maple : cpu = 0.332 (sec), leaf count = 286
\[y \relax (x ) = \frac {\sqrt {4}\, \sqrt {\left (c_{1} \left (a x -\frac {\sqrt {2}\, \sqrt {a}}{4}\right ) {\mathrm e}^{2 x \left (\sqrt {2}\, \sqrt {a}-2 a x \right )}+{\mathrm e}^{-2 x \left (\sqrt {2}\, \sqrt {a}+2 a x \right )} \left (a x +\frac {\sqrt {2}\, \sqrt {a}}{4}\right )\right ) \left (c_{1} {\mathrm e}^{2 x \left (\sqrt {2}\, \sqrt {a}-2 a x \right )}+{\mathrm e}^{-2 x \left (\sqrt {2}\, \sqrt {a}+2 a x \right )}\right )}}{c_{1} {\mathrm e}^{2 x \left (\sqrt {2}\, \sqrt {a}-2 a x \right )}+{\mathrm e}^{-2 x \left (\sqrt {2}\, \sqrt {a}+2 a x \right )}}\]