\[ a y'(x)^m+b y'(x)^n-y(x)=0 \] ✓ Mathematica : cpu = 0.20069 (sec), leaf count = 51
\[\text {Solve}\left [\left \{x=\frac {a m \text {K$\$$5137179}^{m-1}}{m-1}+\frac {b n \text {K$\$$5137179}^{n-1}}{n-1}+c_1,a \text {K$\$$5137179}^m+b \text {K$\$$5137179}^n=y(x)\right \},\{y(x),\text {K$\$$5137179}\}\right ]\]
✓ Maple : cpu = 0.056 (sec), leaf count = 36
\[ \left \{ x-\int ^{y \left ( x \right ) }\! \left ( {\it RootOf} \left ( -a{{\it \_Z}}^{m}-b{{\it \_Z}}^{n}+{\it \_a} \right ) \right ) ^{-1}{d{\it \_a}}-{\it \_C1}=0,y \left ( x \right ) =0 \right \} \]