# How do you find the domain of f(x)=4+e^-x/3?

$D = \setminus m a t h \boldsymbol{R}$
Let's see what your function does. It takes a number $x$, computes ${e}^{- x}$, divides it by three and adds four.
Since you can always divide any number by three, and you can add four to any number, we only need to ask when we can compute ${e}^{- x}$. But the exponential function is computable for any real number, and so the domain of your function is the whole real set.