# Is {(–2, 4), (5, 8), (3, 6), (5, 9)} a function?

$\left\{\begin{matrix}- 2 & 4 \\ 5 & 8 \\ 3 & 6 \\ 5 & 9\end{matrix}\right\}$ is not a function
$f \left(5\right)$ maps into 2 different values: $8 \mathmr{and} 9$