For each of the given functions f(x), find the derivative (f+)'(c) at the given point c, first finding a = (c). (See Theorem 7, page 156 of the Stewart Essential Calculus textbook) 1. f(x) = 4x+9x7; (f)' (c) = c=-13 2. f(x) = x-16x + 84 on the interval [8, 0); c = 24 a = (f)' (c) =