Question

Which of the following is a function?

Answer 1

Answer + Step-by-step explanation:

let f be the relation that we are studying.

f is a function if it associates a unique output (number) to each input (number) .

A. {(2,9), (2,8), (-3,7), (-3,6))

Since f(-3) = 7 and f(-3) = 6

Then

f associates -3 to two different outputs 7 and 6.

Then

f cannot be a function.

B. ((-4,3), (1,0), (1,2), (2,3)}

Since f(1) = 0 and f(1) = 2

Then

f cannot be a function.

C. {(2,1), (4,2), (6,3), (8,4))

f is a function.

D. {(1,2), (-2,3), (1,3), (-2,2)

Since f(-2) = 3 and f(-2) = 2

Then

f cannot be a function.

Answer 2

Answer: C

Step-by-step explanation:

A function only exists if each x-value has only one possible y-value.

C is the only function because each x-value has only one y-value.

The other answer choices have x-values that have multiple y-values. In answer choice A, it has (2,9) and (2,8). In answer choice B, the set has (1, 0) and (1,2). And in answer D, it has (1,3) and (1,2)