5.5+Revisiting+Jean’s+Problem

Big idea: Negative numbers help us to model many real world situations.
__ Essential Question #5: How do I multiply and divide integers? __ __**5.5: Revising Jean's problem**__ **A1: In the table of data you made in prob. 5.2, what range of values did you use for the number of tune-ups?** Answer: I used 1~20 as the range of values for tune-ups. Answer: I used -800$~400$ as my range of values for the profit. Answer: Window setting: Xmin:0 Xmax:20 Xscl:1 Xres:1 Ymin:-800 Ymax:400 Yscl: 60
 * # of tune-ups || 0 || 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11 || 12 || 13 || 14 || 15 || 16 || 17 || 18 || 19 || 20 ||
 * profit made ($'s) || -800 || -740 || -680 || -620 || -560 || -500 || -440 || -380 || -320 || -260 || -200 || -140 || -80 || -20 || 40 || 100 || 160 || 220 || 280 || 340 || 400 ||
 * A2: What range of values did you use for the profit?**
 * B: Enter Jean's profit equation into your calculator. Use the number of tune-ups as the x-variable and the profit as the y-variable. Use your answers to part A to help you decide how to adjust the window settings so that you will be able to see the graph of the profit equation. Press 'GRAPH' to display the graph. Make a sketch of the graph you see on the screen.**

Answer: The break-even point shows as the y-value as 0, and the x-value is between 13 and 14. (Since 13=-20, and 14=40.) I think the x-value is 13.33333333... I think it's because the ratio of the 2 profits is 1:2= 1/3 = 0.333... so 13+0.333=13.333...! Answer: In the table, the break-even point is not shown. The x-values are 13 and 14 and the y-values are -20 and 40. This means that the break-even point is between those 2 values. __**5.5 F.U**__ Answer: Window setting: Xmin:0 Xmax:20 Xscl:1 Xres:1 Ymin:-600 Ymax:600 Yscl: 60 Answer: Window setting: Xmin:0 Xmax:20 Xscl:1 Xres:1 Ymin:-1200 Ymax:0 Yscl: 60
 * C: How is the break-even point shown on the graph?**
 * D: Look at the table of data on your calculator. How is the break-even point shown in the table?**
 * 1. Recall that Jean wrote the equation P= 60t-600 to represent the profit she would make if she bought used tools instead of new tools. Find an appropriate window for viewing the graph of this profit equation. Graph the equation on a calculator. Make a sketch of what you see.**
 * 2. Jean wrote the equation P = 60t-1200 to represent the profit she would make if she advertised in the local paper. Find an appropriate window for viewing the graph of this profit equation. Graph the equation on a calculator. Make a sketch of what you see.**