# How do you determine if (1, 5), (2, 6), (3, 7), (4, 8) is a function?

$\left(x , y\right) \in \left\{\begin{matrix}1 & 5 \\ 2 & 6 \\ 3 & 7 \\ 4 & 8\end{matrix}\right\}$ is a function
Every value of $x$ as only one corresponding value of $y$