18a, 21, 22,

18. MODELING WITH MATHEMATICS The function 24. MULTIPLE REPRESENTATIONS The function y = 3.5x + 2.8 represents the cost y (in dollars) of a taxi ride of x miles. 1.5x + 0.5y = 12 represents the number of hardcover books x and softcover books y you can buy at a used book sale. a. Solve the equation for y. b. Make an input-output table to find ordered pairs for the function. c. Plot the ordered pairs in a coordinate plane. 25. ATTENDING TO PRECISION The graph represents a function. Find the input value corresponding to an output of 2. a. Identify the independent and dependent variables. b. You have enough money to travel at most 20 miles in the taxi. Find the domain and range of the function. ERROR ANALYSIS In Exercises 19 and 20, describe and correct the error in the statement about the relation shown in the table. 26. OPEN-ENDED Fill in the table so that when I is the Input, x independent variable, the relation is a function, and Output, y when I is the dependent variable, the relation is not a function. 19. X The relation Is not a function. One output Is paired with two Inputs. 20. 27. ANALYZING RELATIONSHIPS You select items in a X The relationis a function. The vending machine by pressing one letter and then rangels 1, 2, 3, 4, and 5. one number. ANALYZING RELATIONSHIPS In Exercises 21 and 22, identify the independent and dependent variables. 21. The number of quarters you put into a parking meter affects the amount of time you have on the meter. 22. The battery power remaining on your MP3 player is based on the amount of time you listen to it. 23. MULTIPLE REPRESENTATIONS The balance y (in dollars) of your savings account is a function of the month x. 22 Month, x 2 3 Balance 100 125 150 175 (dollars), y 200 a. Explain why the relation that pairs letter-number combinations with food or drink items is a. Describe this situation in words. a function. b. Write the function as a set of ordered pairs. b. Identify the independent and dependent variables. c. Plot the ordered pairs in a coordinate plane. c. Find the domain and range of the function