Greetings from Brasil...
Note the graph of the function eˣ (or e⁻ˣ). We conclude that for any value of X, the result will be between 0 and +∞.\
So there is no value for X that the result of m.eˣ (or m.e⁻ˣ) is negative.
So you can answer:
For the equation of the statement of the question, with any value of X, we will always obtain a number greater than zero
S = {X | X∈ ℝ}
(OBS: we'll never get zero. We can get very close, but never zero)
