Answer: This is a function
There are no repeated x values. Each x value is paired with exactly one y value. If you had an input of something like x = 3 lead to y = 5 and y = 8 at the same time, then it wouldn't be a function.
If you want, you can graph all five of these points, as is shown in the attached image below. You'll notice that it is impossible to draw a vertical line through more than one of these five points. The graph therefore passes the vertical line test to visually confirm we have a function.