To find the average rate of change, you would have to apply the formula

, and our coordinates in this case are (10, -5) and (30,30). So first, we take the y-value of the second coordinate and subtract it with the y-value of the first coordinate.
This is the formula with the coordinates inserted :

and this would, in turn, make :

. When we add 30 and 5 together, we get 35, and 30-10 is 20. This in fraction form is :
.
Now, we simplify this further. Both numbers can be simplified with 5. This would have us end up with :
. This, in decimal form, would be
1.75.The average rate of change is
1.75.