The mean is like the average. you would add up all the numbers and divide by the amount of numbers there are. in this case, add them all up and divide by 6 because there are 6 different numbers. this will give you your answer
The relation is a function. For a relation to be a function there must be a unique x value for each y value. So this means x's can not repeat, and in this relation, the x-values never repeat. Therefore this is a function.
