finding constant?

Question

1.( Consider the function f (x) = 4-2x^2 on the interval
[-2,7].
(A) Find the average or mean slope of the function on this interval,
f (7)- f (-2)/7-(-2)

(B) By the Mean Value Theorem, we know there exists a c in
the open interval (-2,7) such that f 0(c) is equal to this mean
slope. For this problem, there is only one c that works.
c =?

help......help

Answer 1

The answer to A is an actual number. Plug it in to the left hand side of the definition of x and solve for x. This will be EASY.