In order to determine the average rate of change, use the following formula:
[tex]m=\frac{y_2-y_1}{x_2-x_1}[/tex]
where (x1,y1) and (x2,y2) are a pair of values of the given table.
In this case, you have:
x1 = -13, y1 = 40
x2 = -7, y2 = 16
Replace the previous values of the parameters into the formula for m, as follow:
[tex]m=\frac{16-40}{-7-(-13)}=-\frac{24}{-7+13}=-\frac{24}{6}=-4[/tex]
Hence, the average rate of change is -4
