54. Find f (-2) if f (x) is given by the graph. 2 4 –2 –4 –2 –4 –6 –8 x y 55. Find f (2) if f (x) is given by the graph. 4 2 8 4 –4 –6 –4 –2 –8 x y 56. Find f (-1) if f (x) is given by the graph. 2 2 4 4 –2 –4 –2 –4 –6 x y 57. Find x if f (x) = -6 and f (x) is given by the graph. 2 4 –2 –4 –2 –4 –6 –8 x y 58. Find x if f (x) = 7 and f (x) is given by the graph. 4 4 8 8 –4 –8 –4 –8 x y Write each linear equation in two variables in function notation. Then fi nd f (0), f (3), and f (-2) and write the corresponding ordered pairs. (See Objective 4.) 59. y = 5x - 6 60. y = -7x + 3 61. 4x - y = 9 62. 3x + 5y = 6 63. 2y - 7 = 0 64. 2y + 3 = 0 Solve each problem. (See Objective 5.) 65. Assume that the S&P 500 index historical prices (in dollars) can be modeled by the function f (x) = 1.56x4 - 35x3 + 247x2 - 567x + 1381, where x is the number of years after 2000. a. Use the function to find the S&P 500 index price in 2009. How close is the answer if the actual estimate was 1106? b. Use the function to predict the S&P 500 index for year 2012. 66. Assume that the NASDAQ Composite historical prices (in dollars) can be modeled by the function f (x) = 8.271x4 - 106.302x3 +346.835x2 + 34.085x + 1462.356, where x is the number of years after 2002. a. Use the function to find the NASDAQ composite price in 2006. How close is the answer if the actual estimate was $2457? b. Use the function to predict the NASDAQ composite price for year 2010. 67. An open-top box is constructed by cutting four squares of width x in. from the corners of a rectangular piece of cardboard with dimensions 12 in. by 18 in. and then folding up the sides. The volume of the box is given by the function V(x) = 216x - 60x2 + 4x3, where 0 ≤ x ≤ 6. Evaluate V(2) and interpret the answer. 68. An open-top box is constructed by cutting four squares of width x in. from the corners of a rectangular piece of cardboard with dimensions 24 in. by 30 in. and then folding up the sides. The volume of the box is given by the function V(x) = 720x - 108x2 + 4x3, where 0 ≤ x ≤ 12. Evaluate V(5) and interpret the answer. Mix ’Em Up! Determine if each relation is a function. If not, explain why. 69. The following table shows the 2009 total health expenditure per capita in the selected countries. (Source: http://www.who.int/en) Countries Per Capita Canada $4400 France $4800 Italy $3300 Japan $3300 Republic of Korea $1100 United Kingdom $3300 United States $7400 278 Chapter 3 Linear Equations in Two Variables
hendricks_beginning_algebra_1e_ch1_3
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