Use the graph of below to sketch the graph of each function. (a) (b) (c) (d) (e) 67. Use

Chapter 1, Problem 66

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Use the graph of below to sketch the graph of each function. (a) (b) (c) (d) (e) 67. Use the graph of to find a formula for each of the functions whose graphs are shown. (a) (b) (c) (d) 68. Real Estate Express the value V of a real estate firm in terms of x, the number of acres of property owned. Each acre is valued at $2500 and other company assets total $750,000. 69. Owning a Business You own two restaurants. From 1998 to 2004, the sales (in thousands of dollars) for one restaurant can be modeled by where represents 1998. During the same seven-year period, the sales (in thousands of dollars) for the second restaurant can be modeled by Write a function that represents the total sales for the two restaurants. Use a graphing utility to graph the total sales function. 70. Cost The inventor of a new game believes that the variable cost for producing the game is $0.95 per unit. The fixed cost is $6000. (a) Express the total cost C as a function of x, the number of games sold. (b) Find a formula for the average cost per unit (c) The selling price for each game is $1.69. How many units must be sold before the average cost per unit falls below the selling price? 71. Demand The demand function for a commodity is where p is the price per unit and x is the number of units sold. (a) Find x as a function of p. (b) Find the number of units sold when the price is $10. 72. Cost A power station is on one side of a river that is mile wide. A factory is 3 miles downstream on the other side of the river (see figure). It costs $10/ft to run the power lines on land and $15/ft to run them under water. Express the cost C of running the lines from the power station to the factory as a function of x. 73. Cost The weekly cost of producing x units in a manufacturing process is given by the function The number of units produced in t hours is given by xt 40t. Find and interpret Cxt. Cx 70x 375. 3 x x 2 1 River Factory Power station 1 2 p x 0 14.75 1 0.01x , C Cx. R t 0, 1, 2, 3, 4, 5, 6. 2 254 0.78t, R2 t 0 R t 0, 1, 2, 3, 4, 5, 6 1 480 8t 0.8t 2, R1 x (6, 3) 9 6 3 6 9 3 y x (3, 6) 3 3 3 6 3 y 6 3 3 3 6 9 x (0, 3) y 9 6 3 3 6 3 x (3, 0) y fx x2 y 2x y x 1 1 y x 2 y 1 2x x 2 1 2 1 1 3 2 1 f(x) = x y y x 3 fx x y