Question

Which of the following relations is a function?
(2, 0), (-1, 3), (6, 1), (-1, 5)

(2, 4), (-1, 2), (6, 1), (-7, 2)

(6, 1), (-1, 4), (2, 1), (6, 2)

(2, 4), (-1, 6), (2, 3), (-7, 2)

Answer 1

In a function, the first coordinate will be different in each pair (in other words, the other sets have 'repeat' x values).

Answer 2

A function relates an input to an output.

Answer 3

"f(x) = ... " is the classic way of writing a function.
And there are other ways

Answer 4

soooo....