\[ a y'(x)^m+b y'(x)^n-y(x)=0 \] ✓ Mathematica : cpu = 0.238174 (sec), leaf count = 56
\[\text {Solve}\left [\left \{x=\frac {a m K[1]^{m-1}}{m-1}+\frac {b n K[1]^{n-1}}{n-1}+c_1,y(x)=a K[1]^m+b K[1]^n\right \},\{y(x),K[1]\}\right ]\] ✓ Maple : cpu = 0.073 (sec), leaf count = 36
\[y \relax (x ) = 0\]