Easy,
and here is why:
According to the table, x has a list of numbers and the "F of X" aka: f(x) also has a list of numbers. There is also normally a equation with this kind of problem but since there is not anything I would say about that wouldn't make sense.
Take the number "-1" under f(x) and take a look at the "x" value right next to it, thats your answer.
If you find out that I am wrong, please lets me know in the comments and I will gladly come back and fix anything wrong. Thanks!