\[ y'(x)=x^2 \sqrt {x^2+3 y(x)}+\sqrt {x^2+3 y(x)}+x^3 \sqrt {x^2+3 y(x)}-\frac {2 x}{3} \] ✓ Mathematica : cpu = 0.23122 (sec), leaf count = 65
\[\left \{\left \{y(x)\to \frac {1}{192} \left (-72 c_1 x^4-96 c_1 x^3-288 c_1 x+144 c_1^2+9 x^8+24 x^7+16 x^6+72 x^5+96 x^4+80 x^2\right )\right \}\right \}\]
✓ Maple : cpu = 0.385 (sec), leaf count = 32
\[ \left \{ {\frac {2}{3}\sqrt {{x}^{2}+3\,y \left ( x \right ) }}-{\frac {{x}^{4}}{4}}-{\frac {{x}^{3}}{3}}-x-{\it \_C1}=0 \right \} \]