Question

Which of the following relations is a function:

{(1,2), (1,4), (2,0), (-4,0)}

{(1,4), (2,4), (4,4), (0,4)}

{(0,0), (1,1), (0,-2), (1,-2)}

None of the above

Answer 1

{(1,4), (2,4), (4,4), (0,4)}

why?

Answer 2

thanks!

Answer 3

do you want to know why? and how?