Answer
$A ∪ C= \{3,5$ or $x|x$ is an even integer$\}$
Work Step by Step
$A = \{x|x$ is an even integer $\} $
$A = \{ ...., -6,-4,-2,0,2,4,6,.....\}$
$C = \{ 2,3,4,5\}$
$A ∪ C$ is the set of elements that belong to set A or set C or both.
$A ∪ C= \{3,5$ or $x|x$ is an even integer$\}$