Example Use the bar graph to answer the following questions. Approximate the number of endangered species that are birds. Find the bar labeled birds. From the top of the bar, move horizontally to the left to the scale. There are approximately 78 birds.

Example Use the bar graph to answer the following questions. Approximate the number of endangered species that are birds. b. Which category shows the fewest endangered species? The fewest endangered species is the shortest bar. The shortest bar corresponds to arachnids.

Location of Newport D1 Location of Gatlinburg C2 Location of Robbinsville A5

Example The table gives the number of tornadoes that occurred in the United States for the years shown. (Source: Storm Prediction Center, National Weather Service) a. Write this paired data as a set of ordered pairs of the form (year, number of tornadoes). b. Create a scatter diagram of the paired data. c. What trend in the paired data, if any, does the scatter diagram show? (2007, 1096), (2008, 1692), (2009, 1156), (2010, 1282), (2011, 1693), (2012, 939)

Example The table gives the number of tornadoes that occurred in the United States for the years shown. (Source: Storm Prediction Center, National Weather Service) b. Create a scatter diagram of the paired data. (2007, 1096), (2008, 1692), (2009, 1156), (2010, 1282), (2011, 1693), (2012, 939)

The number of tornadoes varies greatly from year to year. Example The table gives the number of tornadoes that occurred in the United States for the years shown. (Source: Storm Prediction Center, National Weather Service) c. What trend in the paired data, if any, does the scatter diagram show? The number of tornadoes varies greatly from year to year.

Example: Determine whether (3, – 2) is a solution of 2x + 5y = – 4. Let x = 3 and y = – 2 in the equation. 2x + 5y = – 4 2(3) + 5(–2) = – 4 Replace x with 3 and y with –2. 6 + (–10) = – 4 Simplify. – 4 = – 4 True So (3, –2) is a solution of 2x + 5y = – 4

Example: Determine whether (– 1, 6) is a solution of 3x – y = 5. Let x = – 1 and y = 6 in the equation. 3x – y = 5 3(– 1) – 6 = 5 Replace x with – 1 and y with 6. – 3 – 6 = 5 Simplify. – 9 = 5 False So (– 1, 6) is not a solution of 3x – y = 5

Example Graph the linear equation 2x – y = – 4. Let x = 1. 2(1) – y = – 4 Replace x with 1. 2 – y = – 4 Simplify the left side. – y = – 4 – 2 = – 6 Subtract 2 from both sides. y = 6 Multiply both sides by – 1. One solution to the equation is (1, 6).

Example continued: Graph the linear equation 2x – y = – 4. For the second solution, let y = 4. 2x – 4 = – 4 Replace y with 4. 2x = – 4 + 4 Add 4 to both sides. 2x = 0 Simplify the right side. x = 0 Divide both sides by 2. The second solution is (0, 4).

Example continued: Graph the linear equation 2x – y = – 4. For the third solution, let x = – 3. 2(– 3) – y = – 4 Replace x with – 3. – 6 – y = – 4 Simplify the left side. – y = – 4 + 6 = 2 Add 6 to both sides. y = – 2 Multiply both sides by – 1. The third solution is (– 3, – 2).

x y Example continued: (1, 6) (0, 4) (– 3, – 2) Now plot all three of the solutions (1, 6), (0, 4) and (– 3, – 2). Draw the line with arrows that contains the three points.

–4 10 3 Example Complete the table for the equation y = 5x. Replace x with –4. y = 5x y = 5(–4) y = –20 Replace y with 10 20 = 5x 2 = x x y –4 10 3 Replace x with 3. y = 5x y = 5(3) y = 15 x y