table of factors of x, factors of Y; find relationship

[Bridget]

when you are asked to consider a table where there are factors of x listed as 0 1 2 3 4 5 6 and factors of Y listed -5 -4 -3 -2 -1 0 1 and then you are asked to find the relationship demonstrated in that table, what is this called?
I know the answer is Y is equivalent to the difference between the value of x and a constant c, where c is 5 but how do I figure this out?

 

[Deleted member 4993]

  x     y     x-y

  0    -5      5

  1     -4     5

  2     -3     5 .......and so on