22–23. Choices of variables may vary. 22. P( ) = 8 23. E(h) = 7.10h Direct Variation ALGEBRA 1 LESSON 5-5 pages 264–267  Exercises 1. no 2. no 3. yes; –2 4. no 5. yes; 6. yes; 7. yes; – 8. yes; 0.5 9. yes; – 10. y = 5x 11. y = x 22–23. Choices of variables may vary. 22. P( ) = 8 23. E(h) = 7.10h 24. yes; y = 1.8x 25. no 26. yes; y = –1.5x 27. a. or b. = , 52 lb 28. = , 9 mi 29. y = x 30. y = –20x 12. y = – x 13. y = x 14. y = – x 15. y = – x 16. y = – x 17. y = – x 18. y = – x 19. y = 2x 20. y = – x 21. y = x 5 4 9 5 3 2 1 6 5 6 4 3 7 3 50 20 5 2 4 3 1 10 50 20 130 x 4 3 10 3 30 x 3 2 1 6 2 3 1 5 1 5 5-5

b. A line through the origin that is neither vertical nor Direct Variation ALGEBRA 1 LESSON 5-5 31. y = – x 32. y = 6x 33. y = 9x 34. y = – x 35. y = – x 36. y = x 37. a. The ratio is the same for each pair of values. b. A line through the origin that is neither vertical nor horizontal is the graph of a direct variation. 36 25 38. True; a line that is neither horizontal nor vertical can pass through (0, 0) and (–2, 4). 39. False; the line through (0, 3) and (0, 0) is vertical, so it is not a function and is therefore not a direct variation. 40. True; for the equation y = kx, if one side is multiplied by 3, then the other side must be multiplied by 3. 41. y = x 1 32 15 52 27 64 y x 5 2 5-5

Direct Variation 44. y = x 45. a. b. b = w c. Check students’ work. ALGEBRA 1 LESSON 5-5 44. y = x 45. a. b. b = w c. Check students’ work. 46. a. 48 volts b. 0.75 ohms 47. 12 48. –8 49. 8 50. –6 51. 5 52. 2 53. a. c = 1.83g; yes b. c = m or c = 0.07625m 54. A 55. H 56. A 57. B 58. C 42. y = – x 43. 5 2 5 2 1.83 24 1 32 1 32 5 2 5-5

[1] correct answer but no work shown 60. y = 3x 61. y = x Direct Variation ALGEBRA 1 LESSON 5-5 59. [2] y = kx –4 = k(–1) 4 = k y = 4x [1] correct answer but no work shown 60. y = 3x 61. y = x 62. y = 12 – x 63. y = x 64. r > –18 65. c –1.8 66. m < –3 67. a 16.6 68. n < –80 69. t 3.04 70. v – 71. b > 72. 15,600 ships 5 2 > – > – 1 2 1 3 1 6 < – > – 5-5