\[ y(x) f'(x)-f(x) f'(x)+y'(x)=0 \] ✓ Mathematica : cpu = 0.00916306 (sec), leaf count = 18
\[\left \{\left \{y(x)\to c_1 e^{-f(x)}+f(x)-1\right \}\right \}\]
✓ Maple : cpu = 0.011 (sec), leaf count = 15
\[ \left \{ y \left ( x \right ) =f \left ( x \right ) -1+{{\rm e}^{-f \left ( x \right ) }}{\it \_C1} \right \} \]