sorry it's two questions in one these are the last questions i kept get wrong. pls help

For each of the given functions f(a), find the derivative (f 1) (c) at the given point c, first finding a = f (c). a) f(x) = 62 + 8x .c = -14 a = ( f 1 ) ' ( c ) =] b) f(x) = x2 - 12x + 56 on the interval [6, co); c = 21 a = ( f 1 )' ( c ) = The point (3, -1) is on the graph of f(x) = x3 - 3x2 - 1. Find (f !)' (-1)