Answer:Average rate of change = -112
Step-by-step explanation:The average rate of change =

where:
b is the upper limit = 2
f(b) = f(2) = -14(2+4)² - 8 = -512
a is the lower limit = -2
f(a) = f(-2) = -14(-2+4)² - 8 = -64
Substitute with these values in the above equation to get the average rate of change as follows:
average rate of change =

Hope this helps :)