Answer
$\displaystyle \frac{5}{3x}$
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.
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$\displaystyle \frac{4}{9x}+\frac{11}{9x} = \displaystyle \frac{4+11}{9x}$
$= \displaystyle \frac{15}{9x}$
$= \displaystyle \frac{3(5)}{3(3x)}\qquad$... reduce by 3
= $\displaystyle \frac{5}{3x}$