is the following relation a function?

Hello from MrBillDoesMath!
Answer:
Yes.
Discussion:
There appears to be a functional relationship based on the data gives. In particular, each value of "x" has a defined (dependent) value of "y"
Regards,
MrB
P.S. I'll be on vacation from Friday, Dec 22 to Jan 2, 2019. Have a Great New Year!