Question

Which of the following relations is a function?

a{(1, 3), (2, 3), (4,3), (9,3)}

b{(1, 2), (1, 3), (1, 4), (1,5)}

c{(5, 4), (-6, 5), (4, 5), (4, 0)}

d{(6,-1), (1,4), (2, 3), (6, 1)}​

Answer 1

A.

Option A is the answer since a function does NOT contain repeating x-values. In option A, it has the x-values of 1, 2, 4, 9 which do NOT repeat.

Answer 2

a{(1, 3), (2, 3), (4,3), (9,3)}

Explanation:

For the relation to be a function, each x can only go to 1 y

a{(1, 3), (2, 3), (4,3), (9,3)}

function

b{(1, 2), (1, 3), (1, 4), (1,5)}

x=1 goes to 4 different y's so not a function

c{(5, 4), (-6, 5), (4, 5), (4, 0)}

x=4 goes to 2 different y's so not a function

d{(6,-1), (1,4), (2, 3), (6, 1)}​

x = 6 goes to 2 different y's so not a function