The functions shows in the data table is an exponential function.
Answer:

Step-by-step explanation:
Let E be the set of all even positive integers in the universe Z of integers,
i.e
E = {2,4,6,8,10 ....∞}
be the characteristic function of E.
∴

For XE(2)
since x is an element of E (i.e the set of all even numbers)
For XE(-2)
since - 2 is less than 0 , and -2 is not an element of E
For { x ∈ Z: XE(x) = 1}
This can be read as:
x which is and element of Z such that X is also an element of x which is equal to 1.
∴

E = {2,4,6,8,10 ....∞}
Where are the functions?
your question is incomplete?
Answer:
The top right graph.
Step-by-step explanation: