A function's inputs do not repeat. This means that any point with the x-value not repeated with the other points can be added to ensure that it continues as a function.
In this scenario:
{x| x ≠ -7, 4, 0, -2}
A point that does not have the x-value of -7, 0, 4, and -2 could be added to the relation to ensure it continues to be a function.
