Question

Which of the following is a function?

a. {(-4,1),(1,8),(-4,-2)}
b. {(-4,1),(1,-8),(-2,-2)}
c. {(-4,1),(1,-8),(1,-2)}
d. none of these

Answer 1

The expression b. {(-4,1),(1,8),(-4,-2)} is a function

Answer 2

b.

Explanation:

The expression b is a function because the x values are all different.

In fact it is a one-to-one function as there is a different value of y for each value of x.