\[ y'(x)=\frac {x \left (3 a^2 b x^2 y(x)^4+2 a^2 b x^2 y(x)^2+a^3 y(x)^6+a^3 y(x)^4+a^3+3 a b^2 x^4 y(x)^2+a b^2 x^4+b^3 x^6\right )}{a^{7/2} y(x)} \] ✓ Mathematica : cpu = 1.13261 (sec), leaf count = 164
\[\text {Solve}\left [\frac {x^2}{2}-\frac {1}{2} a^{5/2} \text {RootSum}\left [3 \text {$\#$1}^2 a b^2 y(x)^2+\text {$\#$1}^2 a b^2+\text {$\#$1}^3 b^3+3 \text {$\#$1} a^2 b y(x)^4+2 \text {$\#$1} a^2 b y(x)^2+a^{5/2} b+a^3 y(x)^6+a^3 y(x)^4+a^3\& ,\frac {\log \left (x^2-\text {$\#$1}\right )}{3 \text {$\#$1}^2 b^2+6 \text {$\#$1} a b y(x)^2+2 \text {$\#$1} a b+3 a^2 y(x)^4+2 a^2 y(x)^2}\& \right ]=c_1,y(x)\right ]\] ✓ Maple : cpu = 1.094 (sec), leaf count = 352
\[ \left \{ \int _{{\it \_b}}^{x}\!{ \left ( {b}^{3}{{\it \_a}}^{6}+3\,a{b}^{2}{{\it \_a}}^{4} \left ( y \left ( x \right ) \right ) ^{2}+3\,{a}^{2}b{{\it \_a}}^{2} \left ( y \left ( x \right ) \right ) ^{4}+ \left ( y \left ( x \right ) \right ) ^{6}{a}^{3}+a{{\it \_a}}^{4}{b}^{2}+2\, \left ( y \left ( x \right ) \right ) ^{2}{a}^{2}b{{\it \_a}}^{2}+ \left ( y \left ( x \right ) \right ) ^{4}{a}^{3}+{a}^{3} \right ) {\it \_a} \left ( \left ( y \left ( x \right ) \right ) ^{6}{a}^{3}+3\,{a}^{2}b{{\it \_a}}^{2} \left ( y \left ( x \right ) \right ) ^{4}+3\,a{b}^{2}{{\it \_a}}^{4} \left ( y \left ( x \right ) \right ) ^{2}+{b}^{3}{{\it \_a}}^{6}+ \left ( y \left ( x \right ) \right ) ^{4}{a}^{3}+2\, \left ( y \left ( x \right ) \right ) ^{2}{a}^{2}b{{\it \_a}}^{2}+a{{\it \_a}}^{4}{b}^{2}+{a}^{3}+{a}^{{\frac {5}{2}}}b \right ) ^{-1}{a}^{-{\frac {7}{2}}}}\,{\rm d}{\it \_a}+\int ^{y \left ( x \right ) }\!-{{\it \_f} \left ( {a}^{3}{{\it \_f}}^{6}+3\,{a}^{2}b{x}^{2}{{\it \_f}}^{4}+3\,a{b}^{2}{x}^{4}{{\it \_f}}^{2}+{b}^{3}{x}^{6}+{{\it \_f}}^{4}{a}^{3}+2\,{{\it \_f}}^{2}{a}^{2}b{x}^{2}+a{x}^{4}{b}^{2}+{a}^{3}+{a}^{{\frac {5}{2}}}b \right ) ^{-1}}-\int _{{\it \_b}}^{x}\!6\,{\frac { \left ( b{{\it \_a}}^{2}+a{{\it \_f}}^{2} \right ) {\it \_f}\,{\it \_a}\, \left ( a{{\it \_f}}^{2}+b{{\it \_a}}^{2}+2/3\,a \right ) b}{ \left ( {a}^{5/2}b+ \left ( {{\it \_f}}^{6}+{{\it \_f}}^{4}+1 \right ) {a}^{3}+3\,{{\it \_f}}^{2}{{\it \_a}}^{2} \left ( {{\it \_f}}^{2}+2/3 \right ) b{a}^{2}+3\, \left ( {{\it \_f}}^{2}+1/3 \right ) {{\it \_a}}^{4}{b}^{2}a+{b}^{3}{{\it \_a}}^{6} \right ) ^{2}}}\,{\rm d}{\it \_a}{d{\it \_f}}+{\it \_C1}=0 \right \} \]