1. Let f(x) = r + -. (In this problem, we will consider the Mean Value Theorem!) Use desmos.com to look at a graph of this function; you do not have to sketch it. Begin by viewing the graph of f(r) for r E [-15, 15), then zoom in as needed. (a) (2 pts) Why does the Mean Value Theorem apply for the function f(r) on the interval [1, 8), but not on the interval [-1, 1]? (b) (2 pts) Calculate the slope of the secant line between r = 1 & r = 8. Note that the curve passes through the points (1,5) and (8,8.5). (c) (2 pts) Keeping in mind your answers for parts (a) & (b), what is the result of the Mean Value Theorem? (d) (4 pts) Finally, find the value(s) of con the inverval [1,8] that satisfy the Mean Value Theorem. Be sure your work/ reasoning are clear.)