248 CHAPTER 2 Graphs and Functions Find the slope of the line satisfying the given conditions. See Example 5. 41. through 12, -12 and 1-3, -32 42. through 1-3, 42 and 12, -82 43. through 15, 82 and 13, 122 44. through 15, -32 and 11, -72 45. through 15, 92 and 1-2, 92 46. through 1-2, 42 and 16, 42 47. horizontal, through 15, 12 48. horizontal, through 13, 52 49. vertical, through 14, -72 50. vertical, through 1-8, 52 For each line, (a) find the slope and (b) sketch the graph. See Examples 6 and 7. 51. y = 3x + 5 52. y = 2x - 4 53. 2y = -3x 54. -4y = 5x 55. 5x - 2y = 10 56. 4x + 3y = 12 Graph the line passing through the given point and having the indicated slope. Plot two points on the line. See Example 7. 57. through 1-1, 32, m= 3 2 58. through 1-2, 82, m= 2 5 59. through 13, -42, m= -1 3 60. through 1-2, -32, m= - 3 4 61. through A -1 2, 4B, m= 0 62. through A 3 2, 2B, m= 0 63. through A -5 2, 3B, undefined slope 64. through A 9 4, 2B, undefined slope Concept Check Find and interpret the average rate of change illustrated in each graph. 65. 0 1 2 3 4 4 8 12 16 20 x y Year Value of Machine (in thousands of dollars) 66. 0 1 2 3 4 100 200 300 400 x y Month Amount Saved (in dollars) 67. 0 1 2 3 4 2 4 6 8 x y Year Percent of Pay Raise 68. 0 1 2 3 5 10 15 20 x y Year Number of Named Hurricanes Solve each problem. See Example 8. 69. Dropouts In 1980, the number of high school dropouts in the United States was 5085 thousand. By 2016, this number had decreased to 2334 thousand. Find and interpret the average rate of change per year in the number of high school dropouts. Round the answer to the nearest tenth. (Data from 2017 Digest of Education Statistics.) 70. Academy Awards Viewership The percent of all TV households in the United States that tuned in during the live broadcast of the Academy Awards changed from 27.9% in 2014 to 18.9% in 2018. Find and interpret the average rate of change in Academy Awards viewership in percent per year. (Data from Nielsen.)
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