I am studying Complex Analysis with the book Schaum's Complex Variables - from Bailey. See the question bellow and the solution for the alternative b.
There is a point that I do not understand in this proof.
Why |$e^x$ | turns to $e^x$ ?
If x is the Re(z) (the real part of z), |$e^x$ | can be $e^x$ or $e^{-x}$ depending if x is positive or negative.
What error am I making here? Am I using some wrong assumption?
Thanks.

Since $x\in\mathbb R$, $e^x>0$. Therefore, $|e^x|=e^x$.