Is (4,-2), (1,-1), (0,0), (1,1), (4,2) a function?
No this data set is not a function because two points have x coordinates of 4
Hope this helps
in order for something to be a function
for every input or x value, there exists only a single output (or y value)
if you look at the points, are there any x values that have 2 different y values?
if yes, then no its not a function