\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) =1/2\,{x}^{2}+\sqrt {{x}^{3}-6\,y \left ( x \right ) }+{x}^{2}\sqrt {{x}^{3}-6\,y \left ( x \right ) }+{x}^{3}\sqrt {{x}^{3}-6\,y \left ( x \right ) }=0} \]
Mathematica: cpu = 0.326541 (sec), leaf count = 70 \[ \left \{\left \{y(x)\to \frac {1}{96} \left (72 c_1 x^4+96 c_1 x^3+288 c_1 x-144 c_1^2-9 x^8-24 x^7-16 x^6-72 x^5-96 x^4+16 x^3-144 x^2\right )\right \}\right \} \]
Maple: cpu = 0.312 (sec), leaf count = 32 \[ \left \{ -{\frac {1}{3}\sqrt {{x}^{3}-6\,y \left ( x \right ) }}-{\frac {{x}^{4}}{4}}-{\frac {{x}^{3}}{3}}-x-{\it \_C1}=0 \right \} \]