Question

Which of the following relations is not a function?

{(0, 0), (1, 0), (2, 0)}
{(-1, 3), (4, 2), (-1, 5)}
{(1, 2), (3, -5), (-1, 7)}
{(7, -1), (3, -2), (5, -2)}

Answer 1

the second one because an x value is used twice

Answer 2

is it the third?

Answer 3

nvm thanks :)

Answer 4

just remember that and ull get it every time