What is the slope of f(x)=-e^x+3 at x=-1?

$- \frac{1}{e}$
$f \left(x\right) = - {e}^{x} + 3$
$f ' \left(x\right) = - {e}^{x}$
$f ' \left(- 1\right) = - {e}^{- 1} = - \frac{1}{e}$