Linear Graphing

Example 1 Mr Porter wanted to take a taxi into the city. He was told that there were three different routes into the city. The first was 40km and would cost him $85, the second was 31km and would cost $67 and the final route was 35km and would cost $75. What are the two variables? Plot the three points and draw a line through them. What do you notice? Graph the points and write down what you notice. Determine the equation using Graphmatica.

Example 2 After having an enjoyable day in the city Mr Porter wants to return home. Once again he was told that there were three different routes but the prices had changed. The first was 40km and would cost him $125, the second was 31km and would cost $98 and the final route was 35km and would cost $110. What are the two variables? Plot the three points and draw a line through them. Graph the points and write down what you notice. Determine the equation and check this using Graphmatica.

Example 3 Ms Stone wanted to buy some blazers for the Student Representatives. As she was unsure of how many blazers she would need they quoted her for 10, 15 and 25. For 10 blazers the company said it would cost $520, for 15 blazers $770 and finally for 25 blazers $1270. Regardless of how many blazers are ordered the company charges an additional $20 for processing the order. What are the two variables? Plot the three points and draw a line through them. Graph the points and write down what you notice. Determine the equation and check this using Graphmatica.

Example 4 Mr Lawrence is looking at getting a new phone and plan. He goes to one of his local service providers and they quote him prices for three different plans. The first plan costs $25 and provides 180 hours of talk time, the second plan $40 with 270 hours and the final plan $50 with 330 hours. What are the two variables? Plot the three points and draw a line through them. Graph the points and write down what you notice. Determine the equation and check this using Graphmatica.