Question

Which of the following sets of data does NOT represent a function? Set A (x, y) (6, 3) (8 ,4) (5, 7) (9, 2) Set B (x, y) (0, 3) (1, 8) (2, 8) (3, -7) Set C (x, y) (10, 7) (20, 11) (30, 9) (40, 7) Set D (x, y) (3, 9) (2, 2) (8, -3) (2, 1) a: Set A. b: Set B. c: Set C. d: Set D

Answer 1

Answer: D

Explanation:

D contains both (2,2) and (2,1), and fails the definition. D(2) would have to be 2 and 1 at the same time.

Set S is a function if and only if

x ∈ S implies x is an ordered pair,

and

(a,b) and (a,c) ∈ S implies b = c.

Answer 2

set D

Explanation:

For a function we need to have for evety x value, only one value of y.

in set D, we have the points (2, 2) and (2, 1)

this two points have one value of x: x=2

but for the same x we have two values of y: 2 and 1

so this does not obey the requirements to be a functios wich is that for every x, we cannot have more than one value of y.