\[ y'(x)-\sqrt {\frac {\text {a0}+\text {a1} x+\text {a2} x^2+\text {a3} x^3+\text {a4} x^4}{\text {b0}+\text {b1} y(x)+\text {b2} y(x)^2+\text {b3} y(x)^3+\text {b4} y(x)^4}}=0 \] ✓ Mathematica : cpu = 287.031 (sec), leaf count = 23353
\[\text {Too large to show}\]
✓ Maple : cpu = 0.172 (sec), leaf count = 113
\[ \left \{ \int ^{y \left ( x \right ) }\!\sqrt {{{\it \_a}}^{4}{\it b4}+{{\it \_a}}^{3}{\it b3}+{{\it \_a}}^{2}{\it b2}+{\it \_a}\,{\it b1}+{\it b0}}{d{\it \_a}}+\int ^{x}\!-\sqrt {{\frac {{{\it \_a}}^{4}{\it a4}+{{\it \_a}}^{3}{\it a3}+{{\it \_a}}^{2}{\it a2}+{\it \_a}\,{\it a1}+{\it a0}}{{\it b4}\, \left ( y \left ( x \right ) \right ) ^{4}+{\it b3}\, \left ( y \left ( x \right ) \right ) ^{3}+{\it b2}\, \left ( y \left ( x \right ) \right ) ^{2}+{\it b1}\,y \left ( x \right ) +{\it b0}}}}\sqrt {{\it b4}\, \left ( y \left ( x \right ) \right ) ^{4}+{\it b3}\, \left ( y \left ( x \right ) \right ) ^{3}+{\it b2}\, \left ( y \left ( x \right ) \right ) ^{2}+{\it b1}\,y \left ( x \right ) +{\it b0}}{d{\it \_a}}+{\it \_C1}=0 \right \} \]