5 4 The Slope Formula Objective Find slope

5 -4 The Slope Formula Objective Find slope by using the slope formula. Holt Algebra 1

5 -4 The Slope Formula Holt Algebra 1

5 -4 The Slope Formula Example 1: Finding Slope by Using the Slope Formula Find the slope of the line that contains (2, 5) and (8, 1). Use the slope formula. Substitute (2, 5) for (x 1, y 1) and (8, 1) for (x 2, y 2). Simplify. The slope of the line that contains (2, 5) and (8, 1) is. Holt Algebra 1

5 -4 The Slope Formula Check It Out! Example 1 a Find the slope of the line that contains (– 2, – 2) and (7, – 2). Use the slope formula. Substitute (– 2, – 2) for (x 1, y 1) and (7, – 2) for (x 2, y 2). Simplify. =0 The slope of the line that contains (– 2, – 2) and (7, – 2) is 0. Holt Algebra 1

5 -4 The Slope Formula Check It Out! Example 1 b Find the slope of the line that contains (5, – 7) and (6, – 4). Use the slope formula. Substitute (5, – 7) for (x 1, y 1) and (6, – 4) for (x 2, y 2). Simplify. =3 The slope of the line that contains (5, – 7) and (6, – 4) is 3. Holt Algebra 1

5 -4 The Slope Formula Check It Out! Example 2 a The graph shows a linear relationship. Find the slope. Let (2, 2) be (x 1, y 1) and (4, 3) be (x 2, y 2). Use the slope formula. Substitute (2, 2) for (x 1, y 1) and (4, 3) for (x 2, y 2). Simplify. Holt Algebra 1

5 -4 The Slope Formula Check It Out! Example 2 b The graph shows a linear relationship. Find the slope. Let (– 2, 4) be (x 1, y 1) and (0, – 2) be (x 2, y 2). Use the slope formula. Substitute (– 2, 4) for (x 1, y 1) and (0, – 2) for (x 2, y 2). Simplify. Holt Algebra 1

5 -4 The Slope Formula Check It Out! Example 2 d The table shows a linear relationship. Find the slope. Step 1 Choose any two points from the table. Let (0, 0) be (x 1, y 1) and (– 2, 3) be (x 2, y 2). Step 2 Use the slope formula. Substitute (0, 0) for (x 1, y 1) and (– 2, 3) for (x 2, y 2). Simplify Holt Algebra 1

5 -4 The Slope Formula Example 3: Application The graph shows the average electricity costs (in dollars) for operating a refrigerator for several months. Find the slope of the line. Then tell what the slope represents. Step 1 Use the slope formula. Holt Algebra 1

5 -4 The Slope Formula Example 4: Finding Slope from an Equation Find the slope of the line described by 4 x – 2 y = 16. Step 1 Find the x-intercept. Step 2 Find the y-intercept. 4 x – 2 y = 16 4 x – 2(0) = 16 4 x – 2 y = 16 Let y = 0. 4(0) – 2 y = 16 Let x = 0. – 2 y = 16 y = – 8 x=4 Step 3 The line contains (4, 0) and (0, – 8). Use the slope formula. Holt Algebra 1