Identifying Functions

Does the following set of ordered pairs represent y as a function of x?

(-1, 5), (0, 2), (1, -3), (1, 4), (-2, 1)

• Yes, it is a function because none of the inputs repeat.

• No, it is not a function because at least one of the inputs repeat.

Answer explanation

In this list of ordered pairs the points all have unique inputs, so this list of ordered pairs is a function.

Tags

CCSS.8.F.A.1

Does the following set of ordered pairs represent y as a function of x?

(1, 2), (2, 4), (3, 6), (1, 7), (4, 8)

• Yes, it is a function because none of the inputs repeat.

• No, it is not a function because at least one of the inputs repeat.

Answer explanation

In this list of ordered pairs the points (1, 2) and (1, 7) have the same input of 1 and have different outputs of 2 and 7, so this list of ordered pairs is not a function.

Tags

CCSS.8.F.A.1

Does the following set of ordered pairs represent y as a function of x?

(0, 0), (1.5, √3), (√2, 1.2), (2, 1.8), (1.5, 2.5)

• Yes, it is a function because none of the inputs repeat.

• No, it is not a function because at least one of the inputs repeat.

• Yes, it is a function because at least one of the inputs repeat.

• No, it is not a function because none of the inputs repeat.

Answer explanation

In this list of ordered pairs the points (1.5, √3) and (1.5, 2.5) have the same input of 1.5 and have different outputs of √3 and 2.5, so this list of ordered pairs is not a function.

Tags

CCSS.8.F.A.1

Does the following set of ordered pairs represent y as a function of x?

(1, √2), (2, 1.5), (√2, 2), (3, 3)

• Yes, it is a function because none of the inputs repeat.

• No, it is not a function because at least one of the inputs repeat.

• Yes, it is a function because at least one of the inputs repeat.

• No, it is not a function because none of the inputs repeat.

Answer explanation

In this list of ordered pairs the points all have unique inputs, so this list of ordered pairs is a function.

Tags

CCSS.8.F.A.1

Does the graph shown represent y as a function of x?

• Yes, it is a function

• No, it is not a function

Answer explanation

The points (1, 1) and (1, -3) have the same input of 1 and different outputs of 1 and -3, so the graph does not show a function.

Does the graph shown represent y as a function of x?

• Yes, it is a function

• No, it is not a function

Answer explanation

The points shown in this graph all have unique inputs, so the graph does show a function.

Does the graph shown represent y as a function of x?

• Yes, it is a function

• No, it is not a function

Answer explanation

The points (0, 2) and (0, -2) have the same input of 0 and different outputs of 2 and -2, so the graph does not show a function.