What is the average rate of change from x = 2 to x = 3?
2
3
0
5

So, the *average* rate of change is:

(y_final-y_start)/(x_final-x_start) (also for physics!)

In your case:

average rate of change is:

(-1-(-3))/(3-2) = 2/1=2

You can see it's +, so increasing (yeah).

if you would make the interval very small, from x=2 to x=2.00001, and so n, you'd get the concept of slope and derivative (but that's just to let u know)