\[ \boxed { \left ( x \left ( y \left ( x \right ) +x \right ) +a \right ) {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) -y \left ( x \right ) \left ( y \left ( x \right ) +x \right ) -b=0} \]
Mathematica: cpu = 0.041505 (sec), leaf count = 192 \[ \left \{\left \{y(x)\to \frac {1}{x \left (-\frac {x}{\left (a^2+a x^2+b x^2\right )^{3/2} \sqrt {c_1-\frac {1}{(a+b) \left (a^2+a x^2+b x^2\right )}}}-\frac {a}{-a^2-a x^2-b x^2}\right )}-\frac {a+x^2}{x}\right \},\left \{y(x)\to \frac {1}{x \left (\frac {x}{\left (a^2+a x^2+b x^2\right )^{3/2} \sqrt {c_1-\frac {1}{(a+b) \left (a^2+a x^2+b x^2\right )}}}-\frac {a}{-a^2-a x^2-b x^2}\right )}-\frac {a+x^2}{x}\right \}\right \} \]
Maple: cpu = 0.062 (sec), leaf count = 146 \[ \left \{ y \left ( x \right ) ={\frac {1}{-{a}^{2}+{\it \_C1}} \left ( -a bx-{\it \_C1}\,x+\sqrt {{\it \_C1}\,{a}^{2}{x}^{2}+2\,{\it \_C1}\,ab{x }^{2}+{\it \_C1}\,{b}^{2}{x}^{2}+{\it \_C1}\,{a}^{3}+{\it \_C1}\,{a}^{ 2}b-{{\it \_C1}}^{2}a-{{\it \_C1}}^{2}b} \right ) },y \left ( x \right ) =-{\frac {1}{-{a}^{2}+{\it \_C1}} \left ( abx+{\it \_C1}\,x+\sqrt {{ \it \_C1}\,{a}^{2}{x}^{2}+2\,{\it \_C1}\,ab{x}^{2}+{\it \_C1}\,{b}^{2} {x}^{2}+{\it \_C1}\,{a}^{3}+{\it \_C1}\,{a}^{2}b-{{\it \_C1}}^{2}a-{{ \it \_C1}}^{2}b} \right ) } \right \} \]