Suppose f(x)= 7-8x^2, by the Mean Value Theorem, we know there exists a c in the open interval (-2,5) such that f'(c) is equal to this mean slope. For this problem, there is only one c that works. Find it.

f(-2) = -25

f(5) = -193

mean slope is (-193+25)/7

f' = -16x

find where f' = the mean slope. That is c. Make sure it is in (-2,5).