Question

Which represents a function?

A 2-column table with 5 rows. The first column is labeled x with entries negative 10, negative 5, 0, 5, 10. The second column is labeled y with entries 84, 31.5, 4, 1.5, 24.

A mapping diagram shows a relation, using arrows between domain and range for the following ordered pairs: (8, negative 4), (negative 2, 10), (negative 2, negative 7). In the domain, the number 3 does not have a relation to a number in the range.

A series of ordered pairs: (4, 5), (6, negative 2), (negative 5, 0), (6, 1)

Answer 1

Only the 2-column table is a function.

Why:
- Table: each x-value (-10, -5, 0, 5, 10) has exactly one y-value — so it is a function.
- Mapping diagram: -2 maps to two different outputs (10 and -7), and 3 has no output — so it is not a function.
- Ordered pairs: x = 6 appears twice with different y-values (-2 and 1) — so it is not a function.