the table represents a linear function?

You could take any 2 points given in the table and use the slope formula to find the slope of this linear function.  Can you do that?

Example:  one point is (-2,8); another is (2,-16).  I see immediately that if x increases, y decreases, so I know that the slope is negative.
         rise         -16-8         -24
m = ---------  = ----------- = -------- = ???
          run          2-(-2)          4