The question shows a set of numbers called the input, these values are the domain and the the ones called the output are the range. Therefore;
[tex]\begin{gathered} \text{Domain}=\mleft\lbrace4,\text{ 5}\mright\rbrace \\ \text{Range}=\mleft\lbrace2,\text{ 3, 4}\mright\rbrace \end{gathered}[/tex]
The relationship shown in the question IS NOT a function. This is because a function must only have one value of output for each value of input.
Since the input 4 has two value which are 2 and 4 in the set of outputs, then it fails to qualify as a function.
