## Calculus, 10th Edition (Anton)

$x=-2$
Factor the left side of the equation to get $e^{-x}(x+2)=0$. If one of the factors equal zero, the entire expression equals zero. $e^{-x}$ can never equal zero, so there is no solution. Solving $x+2=0$ by subtracting two from each side leaves $x=-2$.