Which relation represents a function?

O A. { (1, 1), (4, 6), (4, 9) }

OB. { (2, 3), (2,5), (3,5) }

OC. { (3, 7), (5, 9), (7, 9) }

OD. { (4, 8), (4, 5), (6,3) }

Answer: C

Step-by-step explanation: First, it's important to understand the definition of a function so we know how to solve the problem.

A function is a relation in which each x-coordinate corresponds to exactly one y-coordinate.

First, let's look at A.

{ (1, 1), (4, 6), (4, 9) }

In the relation shown above, notice that the x-coordinate 4 appears twice. In one case, 4 corresponds to 6 and in the other case, 4 corresponds to 9. Since the x-coordinate 4 corresponds to more than one y-coordinate, this relation does not represent a function.

Now let's look at B.

{ (2, 3), (2,5), (3,5) }

In the same way as the first relation we did, this relation is not a function since each x-coordinate does not have one unique y-coordinate. In one case, 2 corresponds with 3 and in the other, 2 corresponds to 5.

Since each x-coordinate does not correspond to exactly one y-coordinate, the relation shown here does not represent a function.

Now let's look at C.

{ (3, 7), (5, 9), (7, 9) }

Notice that each of the x-coordinates shown above have only one unique y-coordinate. In other words, each x-coordinate is paired with a single y-coordinate and this is an example of a function.

Even though we have our answer, let's just look at D just to be sure.

{ (4, 8), (4, 5), (6,3) }

Notice that 4 corresponds to 8 in one case and 5 in the other so this would not be an example of a function.

So, c will be your answer.