Answer
$(A\cap B)\cup C=\{1,3,4,6\}$.
Work Step by Step
The given sets are
$A=\{1,3,4,5,9\},B=\{2,4,6,7,8\}$ and $C=\{1,3,4,6\}$
The symbol $\cap$ means the set containing common elements of the given sets.
$A\cap B=\{4\}$
The symbol $\cup$ means the set containing all the elements of the given sets.
$(A\cap B)\cup C=\{1,3,4,6\}$
Hence, the answer is $(A\cap B)\cup C=\{1,3,4,6\}$.
