\[ \boxed { {\frac {{\rm d}^{2}}{{\rm d}{x}^{2}}}y \left ( x \right ) -6\, \left ( y \left ( x \right ) \right ) ^{2}+4\,y \left ( x \right ) =0} \]
Mathematica: cpu = 0.366546 (sec), leaf count = 373 \[ \text {Solve}\left [\frac {4 \left (\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]\right ) \left (y(x)-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,1\right ]\right ) \left (y(x)-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]\right ) \left (y(x)-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]\right ) F\left (\sin ^{-1}\left (\sqrt {\frac {\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]-y(x)}{\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]}}\right )|\frac {\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]}{\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,1\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]}\right ){}^2}{\left (c_1+4 y(x)^3-4 y(x)^2\right ) \left (\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,1\right ]\right ) \left (\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]\right )}=\left (c_2+x\right ){}^2,y(x)\right ] \]
Maple: cpu = 0.110 (sec), leaf count = 59 \[ \left \{ \int ^{y \left ( x \right ) }\!{\frac {1}{\sqrt {4\,{{\it \_a}} ^{3}-4\,{{\it \_a}}^{2}+{\it \_C1}}}}{d{\it \_a}}-x-{\it \_C2}=0,\int ^{y \left ( x \right ) }\!-{\frac {1}{\sqrt {4\,{{\it \_a}}^{3}-4\,{{ \it \_a}}^{2}+{\it \_C1}}}}{d{\it \_a}}-x-{\it \_C2}=0 \right \} \]