256 Chapter 3 Graphing Linear Equations in Two Variables Concept 1: Interpreting a Linear Equation in Two Variables 9. The minimum hourly wage, y (in dollars per hour), in the United States can be approximated by the equation y 0.14x 1.60. In this equation, x represents the number of years since 1970 (x 0 represents 1970, x 5 represents 1975, and so on). (See Example 1.) a. Use the equation to approximate the minimum wage in the year 1980. b. Use the equation to predict the minimum wage in 2015. c. Determine the y-intercept. Interpret the meaning of the y-intercept in the context of this problem. d. Determine the slope. Interpret the meaning of the slope in the context of this problem. 10. The average daily temperature in January for cities along the eastern seaboard of the United States and Canada generally decreases for cities farther north. A city’s latitude in the northern hemisphere is a measure of how far north it is on the globe. The average temperature, y (measured in degrees Fahrenheit), can be described by the equation where x is the latitude of the city. y 2.333x 124.0 a. Use the equation to predict the average daily temperature in January for Philadelphia, Pennsylvania, whose latitude is . Round to one decimal place. 40.0°N 8 7 6 5 4 3 Federal Minimum Hourly Wage by Year 2 1 y 0.14x 1.60 0 0 5 10 15 20 25 30 35 40 Minimum Wage ($/hr) 80 Year (x 0 represents the year 1970) Average Daily Temperature in January along the Eastern Seaboard by Latitude 70 60 50 40 30 20 10 y y 0 0 10 20 30 40 50 Temperature (°F) Latitude b. Use the equation to predict the average daily temperature in January for Edmundston, New Brunswick, 47.4°N Canada, whose latitude is . Round to one decimal place. c. What is the slope of the line? Interpret the meaning of the slope in terms of latitude and temperature. d. From the equation, determine the value of the x-intercept. Round to one decimal place. Interpret the meaning of the x-intercept in terms of latitude and temperature. 11. Veterinarians keep records of the weights of animals that are brought in for examination. Grindel, the cat, weighed 42 oz when she was 70 days old. She weighed 46 oz when she was 84 days old. Her sister, Frisco, weighed 40 oz when she was 70 days old and 48 oz at 84 days old. x x y 2.333x 124.0 (Source: U.S. National Oceanic and Atmospheric Administration) 50 Weight vs. Age (70, 42) (84, 48) 0 65 70 75 80 85 Weight (oz) Age (days) (84, 46) (70, 40) 40 30 20 10 y x Grindel Frisco a. Compute the slope of the line representing Grindel’s weight. b. Compute the slope of the line representing Frisco’s weight. c. Interpret the meaning of each slope in the context of this problem. d. Which cat gained weight more rapidly during this time period?
miller_beginning_intermediate_algebra_4e_ch1_3
To see the actual publication please follow the link above