In Problems 13–24, use the graph of the function f given.

In the section opener, we saw that 80x – 8000 f(x) 30 s xs 100 110 models the government tax revenue, f(x), in tens of billions of dollars, as a function of the tax rate percentage, x. Use this function to solve Exercises 55–58. Round to the nearest ten billion dollars. 55. Find and interpret f(30). Identify the solution as a point on the graph of the function in Figure 6.4 on page 439. 56. Find and interpret f(70). Identify the solution as a point on the graph of the function in Figure 6.4 on page 439. 57. Rewrite the function by using long division to perform (80x - 8000) - (x - 110). Then use this new form of the function to find f(30). Do you obtain the same answer as you did in Exercise 55? Which form of the function do you find easier to use? 58. Rewrite the function by using long division to perform (80x – 8000) - (x – 110).

10, 14, 16, Page 52. Find the real and imaginary parts of the following functions: (a) f(z) = −3z + 2z − i; - (b) f(z) = 2 + 1/ z;

1. In the figure below, find the number(s) "c" that Rolle's Theorem promises (guarantees). 10 For Problems 2–4, verify that the hypotheses of Rolle's Theorem are satisfied for each of the func- tions on the given intervals, and find the value of the number(s) "c" that Rolle's Theorem promises. 2. (a) f(x) = x² on |-2, 2 (b) f(x) = x² =5x +8 on [0,5] 3. (a) f(x) = sin(x) on [0, 7] (b) f(x) = sin(x) on [A,57]| 4. (a) f(x) = r-x+3 on | 1,1] (b) f(x) = x cos(x) on (0, [0, 1

In Exercises 57–62, find the zeros of ƒ and sketch its graph by plotting points. Use symmetry and increase/decrease information where appropriate. 57. f(x) — х? — 4 58. f(x) = 2x2 – 4 %3D %3D 59. f(x) — х3 — 4х 60. f(x) — х3 61. f(x) =2 – x3 62. f(x) = (x – A)¾i+ate Wind

Exercises 121–140: (Refer to Examples 12–14.) Complete the following for the given f(x). (a) Find f(x + h). (b) Find the difference quotient of f and simplify. 121. f(x) = 3 122. f(x) = -5 123. f(x) = 2x + 1 124. f(x) = -3x + 4 %3D 125. f(x) = 4x + 3 126. f(x) = 5x – 6 127. f(x) = -6x² - x + 4 128. f(x) = x² + 4x 129. f(x) = 1 – x² 130. f(x) = 3x² 131. f(x) = 132. /(x) 3D글 = = 132. f(: 133. f(x) = 3x² + 1 134. f(x) = x² –- 2 135. f(x) = -x² + 2r 136. f(x) = -4xr² + 1 137. f(x) = 2x - x +1 138. f(x) = x² + 3x - 2 139. f(x) = x' 140. f(x) = 1 – x

In Problems 49–56, for each graph of a function y = f(x), find the absolute maximum and the absolute minimum, if they exist. Identify any local maximum values or local minimum values.

In Problems 23–30, use the given zero to find the remaining zeros of each function. 23. f(x) = x - 4x² + 4x – 16; zero: 2i 24. g(x) = x + 3x? + 25x + 75; zero: -5i 25. f(x) = 2x* + 5x + 5x? + 20x – 12; zero: -2i 26. h(x) = 3x4 + 5x + 25x? + 45x – 18; zero: 3i %3D 27. h(x) = x* – 9x + 21x? + 21x – 130; zero: 3 - 2i 29. h(x) = 3x³ + 2x* + 15x³ + 10x2 – 528x – 352; zero: -4i 28. f(x) = x* – 7x + 14x2 – 38x – 60; zero:1 + 3i 30. g(x) = 2x – 3x* – 5x – 15x² – 207x + 108; zero: 3i