Answer
$A\cup C=\{a,b,c,d,f,g\}$
Work Step by Step
$A=\{a,b,c\}$ $;$ $C=\{a,d,f,g\}$
$A\cup C$
The union of two sets is a set formed by all the elements included in both sets.
The union of $A$ and $C$ has all the elements included in $A$ and all the elements included in $C$, as follows:
$A\cup C=\{a,b,c,d,f,g\}$
