# How do you differentiate f(x) = (e^x-4x)/(1-xe^x) using the quotient rule?

$f ' \left(x\right) = \frac{{e}^{x} + {e}^{2 x} - 4 {x}^{2} {e}^{x} - 4}{1 - x {e}^{x}} ^ 2$
$f ' \left(x\right) = \frac{\left({e}^{x} - 4\right) \left(1 - x {e}^{x}\right) - \left({e}^{x} - 4 x\right) \left(- {e}^{x} - x {e}^{x}\right)}{1 - x {e}^{x}} ^ 2$