Answer
\begin{align*}
&\text{NOT a Function
}\\&\text{Domain: }\{
1,3,4,10
\}\\&\text{Range: }\{
5,6,8,12
\}
\end{align*}
Work Step by Step
In the given set of ordered pairs, \begin{align*}\left\{
(4,5),(1,5),(3,8),(4,6),(10,12)
\right\}\end{align*} the first coordinates are not unique ($4$ was repeated). Hence, the given set does NOT define a function.
The domain is the set of all first coordinates, while the range is the set of all second coordinates.
Hence, the given set has the following characteristics:
\begin{align*}
&\text{NOT a Function
}\\&\text{Domain: }\{
1,3,4,10
\}\\&\text{Range: }\{
5,6,8,12
\}
.\end{align*}
