Answer:
1, not a function because the -2 x repeats it's self twice, and only y functions can repeat
2, yes it is because it is a straight line and none of the x functions repeat
3, yes because none of the x functions repeat
4, yes because all the x functions only have one y function
5, no because 16x repeats
6, no because 2x goes to the same number twice
Explanation: