State the domain of the following relation and state if it is a function.

(3, 2), (4, 1), (4, 5), (5, 1)

A. {3, 4, 5}; Yes

B. {1, 2, 5}; Yes

C. {3, 4, 5}; No

D. {1, 2, 5}; No

The domain of a function is all of the X values, and if they are all different, the relation is a function.

The X values are the first number in the parenthesis, so the domain is {3,4,4,5} As you can see, there are two 4's in the domain, so this relation is not a function. Thus, the answer is C - {3,4,5}; No