\[ \boxed { {\frac {\rm d}{{\rm d}x}}y \left ( x \right ) +a \left ( y \left ( x \right ) \right ) ^{2}-b=0} \]
Mathematica: cpu = 0.040505 (sec), leaf count = 43 \[ \left \{\left \{y(x)\to \frac {\sqrt {b} \tanh \left (\sqrt {a} \sqrt {b} c_1+\sqrt {a} \sqrt {b} x\right )}{\sqrt {a}}\right \}\right \} \]
Maple: cpu = 0.031 (sec), leaf count = 29 \[ \left \{ y \left ( x \right ) ={\frac {1}{a}\tanh \left ( {\it \_C1}\, \sqrt {ab}+x\sqrt {ab} \right ) \sqrt {ab}} \right \} \]
Sage: cpu = 0 (sec), leaf count = 0 \[ \text {Maxima was unable to solve this ODE} \]