Respuesta :

himynameisnounow

Answer:

#3 and #4 and #6

Step-by-step explanation:

a function is when there is only one x for one y, so if two points have the same x value but different y value, they cannot be a function

asterisk13

Answer:

The third one, fourth one, and sixth one.

Step-by-step explanation:

If there are repeating x values in the domain, the function would not be valid, for vertical lines would form. Every input (domain) must only have one output (range), but every output can have multiple different inputs.