Answer
$\displaystyle \frac{18}{x}$
Work Step by Step
To add rational expressions with the same denominator,
add numerators and place the sum over the common denominator.
If possible, factor and simplify the result.
---
$\displaystyle \frac{5}{x}+\frac{13}{x} = \displaystyle \frac{5+13}{x}$
= $\displaystyle \frac{18}{x}$