\[ y''(x)-6 y(x)^2+4 y(x)=0 \] ✓ Mathematica : cpu = 0.3216 (sec), leaf count = 373
\[\text {Solve}\left [\frac {4 \left (\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]\right ) \left (y(x)-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,1\right ]\right ) \left (y(x)-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]\right ) \left (y(x)-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]\right ) F\left (\sin ^{-1}\left (\sqrt {\frac {\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]-y(x)}{\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]}}\right )|\frac {\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]}{\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,1\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]}\right ){}^2}{\left (4 y(x)^3-4 y(x)^2+c_1\right ) \left (\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,1\right ]\right ) \left (\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,3\right ]-\text {Root}\left [4 \text {$\#$1}^3-4 \text {$\#$1}^2+c_1\& ,2\right ]\right )}=(x+c_2){}^2,y(x)\right ]\] ✓ Maple : cpu = 0.17 (sec), leaf count = 59
\[ \left \{ \int ^{y \left ( x \right ) }\!{\frac {1}{\sqrt {4\,{{\it \_a}}^{3}-4\,{{\it \_a}}^{2}+{\it \_C1}}}}{d{\it \_a}}-x-{\it \_C2}=0,\int ^{y \left ( x \right ) }\!-{\frac {1}{\sqrt {4\,{{\it \_a}}^{3}-4\,{{\it \_a}}^{2}+{\it \_C1}}}}{d{\it \_a}}-x-{\it \_C2}=0 \right \} \]