Pre-Cal Plz Help Me and thank you in advance

Question

State whether the following solution sets are from a function or non-function

1.(2,6),(-3,6),(4,9),(2,10)

2.(0,-2),(1,3),(2,3),(3,7)

3.(-2,4)(-1,1),(0,0),(1,1)

4.(-2,4),(-2,6),(0,3)(3,7)

Answer 1

Dear Ana J.,

1) This is a nonfunction because (2,6) and (2,10) have the same x value which is 2.

2) This is a function.

3) This is a function.

4) This is a nonfunction because (-2,4) and (-2,6) have the same x value which is -2.

Answer 2

If an x value is repeated it is not a function. This rule from Algebra 1.

Is this really a pre-calc question?