You can find the slope of a linear function by taking two points and finding the change in y over change in x.
Hm, but the values you gave for the tables don't make sense for a linear function/relationship. But let's just pick two points as an example.
So two points you can pick are (-2, 13) and (1, -3).
The slope, change in y over change in x is in other words (y2 - y1 / x2 - x1), where (x1, y1) is one point and (x2, y2) is another.
(-3 - 13) / (1 - -2) = -16/3 = -(16/3)
Or you could have switched up the order of those coordinates but you still get the same answer.
(13 - -3) / (-2 - 1) = 16 / (-3) = -(16/3)
