\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) -\sqrt {{\frac {{\it a4}\,{x}^{4}+{\it a3}\,{x}^{3}+{\it a2}\,{x}^{2}+{\it a1}\,x+{\it a0}}{{\it b4}\, \left ( y \left ( x \right ) \right ) ^{4}+{\it b3}\, \left ( y \left ( x \right ) \right ) ^{3}+{\it b2}\, \left ( y \left ( x \right ) \right ) ^{2}+{\it b1}\,y \left ( x \right ) +{\it b0}}}}=0} \]
Mathematica: cpu = 159.017193 (sec), leaf count = 23353 \[ \text {Unable to compile Latex} \]
Maple: cpu = 0.110 (sec), leaf count = 113 \[ \left \{ \int ^{y \left ( x \right ) }\!\sqrt {{{\it \_a}}^{4}{\it b4}+{ {\it \_a}}^{3}{\it b3}+{{\it \_a}}^{2}{\it b2}+{\it \_a}\,{\it b1}+{ \it b0}}{d{\it \_a}}+\int ^{x}\!-\sqrt {{\frac {{{\it \_a}}^{4}{\it a4 }+{{\it \_a}}^{3}{\it a3}+{{\it \_a}}^{2}{\it a2}+{\it \_a}\,{\it a1}+ {\it a0}}{{\it b4}\, \left ( y \left ( x \right ) \right ) ^{4}+{\it b3} \, \left ( y \left ( x \right ) \right ) ^{3}+{\it b2}\, \left ( y \left ( x \right ) \right ) ^{2}+{\it b1}\,y \left ( x \right ) +{\it b0}}}} \sqrt {{\it b4}\, \left ( y \left ( x \right ) \right ) ^{4}+{\it b3}\, \left ( y \left ( x \right ) \right ) ^{3}+{\it b2}\, \left ( y \left ( x \right ) \right ) ^{2}+{\it b1}\,y \left ( x \right ) +{\it b0}}{d{\it \_a}}+{\it \_C1}=0 \right \} \]