Question

Is (4,-2), (1,-1), (0,0), (1,1), (4,2) a function?

Answer 1

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

Answer 2

No this data set is not a function because two points have x coordinates of 4

Hope this helps