Answer:
No
Explanation:
(the image is fuzzy so you can't really see the lines)
It seems that when x = 1, f(x) is both 4 and 5.
While two different x values can equal the same y value, one single x value cannot be equal to more than one value.
If this was a function that could be graph, there would be an extra dot at (1, 4) or (1, 5) since 1 is equal 4 or 5. This is why it is not a function.