Which relation is also a function?

{ (0, 3), (1, 2), (1, 4), (2, 1) }

{ (-1, 3), (0, 2), (3, - 1), (3, 2) }

{ (2, - 4), (2, - 2), (2, 1), (2, 3) }

{ (-4, - 3), (0, - 3), (1, - 3), (4, - 3) }

A function will not have any repeating x values ... they all have to be different. They can have repeating y values, just not the x ones.

so ur sets of numbers are all set up like (x, y). Now look through ur answer choices and which one has all different x values? That will be ur function.

ur answer is : { (-4,-3), (0,-3), (1,-3), (4,-3) } ... and as u can see, all the x values {-4,0,1,4} are different.