We have
X: -2, -1, 0, 1, 2
Y: -7, -2, 1, -2, -7
the domain is the set of all the possible values for x, in this case, we have
{-2, -1, 0, 1, 2}
the range is the set of all possible values of y in this case we have
{-7, -2, 1}
With this information, we can say it is a function,