Are both of theses sets of orderd pairs a function? {(4,2) (3,15) (2,18) (1,21)} {(-6,8) (-3,4) (3,0) (6,-4)}

Question

I don't understand if they are functions or not because they both have no repeating x-factors.

Answer 1

the 1st set has one point (3,15), the 2nd set has a point (3,0)

that's one x value with 2 corresponding y values. Plot them, you can draw a vertical line that goes through both points. Under the vertical line test, they are not a function.