(2,3) and (2,5) cause the relation to not be a function
Explanation:
The input x = 2 leads to y = 3 and y = 5 at the same time for both points. A function is where any input x leads to exactly one y output only. So we'd need to get rid of one of those mentioned points to be able to have a function.
If you graphed the points on the same xy grid, then you'd see (2,3) and (2,5) vertically aligned. These two points cause the vertical line test to fail. This will give a visual indication we do not have a function.
Put another way, if x repeats itself then we don't have a function. The y value is allowed to repeat. So we could have something like (1,2) and (5,2) be part of a function.