1.5 part 1 question 18 Determine whether the table represents functions or not assume that the input is in the left column or top row (explain your answer)

A function is a relation in which each element of the input is associated with exactly one element of the output. For example:
In this case, we have:
As we can see, the table does not represent a function because there is a value in the input set that is associated with two values in the output set.