Then find all values of c in the interval a b satisfying f

Question

Decide whether the function f = 4 -x² satisfies the hypotheses of the MVP on the interval [a, b] = [-1, 0].

Then find all values of c in the interval [a, b] satisfying f' (c) = {f(b) - f(a)} / (b-a) If there is more more than one enter them as a comma separated list.