Use a mapping diagram to determine whether the relation is a function. {(−1, 5), (3, 4), (2, 5), (−1, −3)}

The domain contains three numbers {-1,3,2} and the range contains three numbers {5,4,-3}.
Following the procedure, we draw an arrow from -1 to 5, 3 to 4, 2 to 5 and -1 to -3.

Since -1 is the origin of two arrows pointing to 5 and -3, the relation is NOT a function.