A-48 Answers to Selected Exercises [9.3] 12. -3 13. 59 [9.4] 14. 7 x - 5 + 3 x + 4 15. -1 x + 2 + 6 x + 4 + -3 x - 1 9.5 Exercises 1. 4 3. -1 5. x2 + x = 2 13. Consider the graphs. A line and a parabola cannot intersect in more than two points. 15. 511, 12, 1-2, 426 17. E12, 12, A1 3 , 4 9B F 19. 512, 122, 1-4, 026 21. E A - 3 5 , 7 5B , 1-1, 12F 23. 512, 22, 12, -22, 1-2, 22, 1-2, -226 25. 510, 026 27. E Ai, 26 B , A -i, 26 B , Ai, -26B , A -i, -26 B F 29. 511, -12, 1-1, 12, 11, 12, 1-1, -126 31. ∅ 33. E A 26, 0B , A -26, 0B F 35. E1-3, 52, A15 4 , -4B F 37. E A4, - 1 8B , A -2, 1 4B F 39. 513, 42, 1-3, -42, Q423 3 i, -3i 23 R, Q- 4 23 3 i, 3i 23RF 41. E A 25, 0B , A -25, 0B , A 25, 25 B , A -25, -25 B F 43. 513, 52, 1-3, -52, 15i, -3i2, 1-5i, 3i26 45. 515, 02, 1-5, 02, 10, -526 47. 513, -32, 13, 326 49. 512, 22, 1-2, -22, 12, -22, 1-2, 226 51. 51-0.79, 0.622, 10.88, 0.7726 53. 510.06, 2.8826 55. -14 and -3 57. 8 and 6, 8 and -6, -8 and 6, -8 and -6 59. 27 and 6, -27 and -6 61. 5 m and 12 m 63. yes 65. y = 9 67. First answer: length = width: 6 ft; height: 10 ft Second answer: length = width: 12.780 ft; height: 2.204 ft 71. (a) 160 units (b) $3 73. (a) Revenue for public colleges from state sources is decreasing, and revenue from tuition/fees is increasing. (b) 2014 to 2015 (c) The sources of revenue were equal in 2011, when they each contributed about 19%. 75. Translate the graph of y = x to the right 1 unit. 76. Translate the graph of y = x2 down 4 units. 77. y = e x - 1 1 - x if if x Ú 1 x 61 78. x2 - 4 = x - 1 1x Ú 12; x2 - 4 = 1 - x 1x 612 79. 1 + 213 2 ; -1 - 221 2 80. EQ1 + 213 2 , -1 + 213 2 R , Q -1 - 221 2 , 3 + 221 2 RF Summary Exercises on Systems of Equations 1. 51-3, 226 2. 51-5, -426 3. E A0, 25 B , A0, -25 B F 4. 51-10, -6, 2526 5. E A4 3 , 3B , A - 1 2 , -8B F 6. 51-1, 2, -426 7. 515z - 13, -3z + 9, z26 8. E1-2, -22, A14 5 , - 2 5B F 9. ∅ 10. 51-3, 3, -326 11. E A -3 + i27, 3 + i27 B , A -3 - i27, 3 - i27 B F 12. 512, -5, 326 13. 511, 22, 1-5, 1426 14. ∅ 15. 510, 1, 026 16. E A3 8 , -1B F 17. 51-1, 0, 026 18. 51-8z - 56, z + 13, z26 19. E10, 32, A - 36 17 , - 3 17B F 20. 512y + 3, y26 21. 511, 2, 326 22. E A2 + 2i22, 5 - i22 B , A2 - 2i22, 5 + i22 B F 23. 512, 2, 526 24. ∅ 25. 514, 22, 1-1, -326 26. 51-2, -4, 026 27. E A 213, i22B , A -213, i22B , A 213, -i22B , A -213, -i22 B F 28. 51-z - 6, 5, z26 29. 511, -3, 426 30. E A - 16 3 , - 11 3 B , 14, 12F 31. 51-1, -2, 526 32. ∅ 33. 511, -32, 1-3, 126 34. 511, -6, 226 35. 51-6, 92, 1-1, 426 36. 512, -3, 126 9.6 Exercises 1. C 3. B 5. does not 7. 12, -52 9. dashed 11. x x + 2y ≤ 6 6 3 y 0 13. x 2 2x + 3y ≥ 4 y 0 4 3 15. x 3x – 5y > 6 2 y 0 6 5 – 17. x y 0 5x < 4y – 2 2 5 1 2 – 19. x x ≤ 3 3 y 0 21. x 0 1 y 1 y < 3x2 + 2 5 23. x 0 1 y 3 y > (x – 1)2 + 2 (1, 2) 25. 0 x y x2 + (y + 3)2 ≤ 16 (0, –3) 27. x 0 2 y y > 2x+ 1 2 29. above 31. B 33. C 35. A
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