200 likes | 398 Views
8.4 Slope. Objectives: To find the slope of a line given two points on the line To Find Slope Given an Equation of a Line To describe slope for horizontal and vertical lines. 10. 8. 6. 4. Slope =. 2. 10. 6. 8. -2. -4. 2. 4. -2. -4. -6. -8. -10. Slope. run. rise. 10. 8.
E N D
8.4 Slope Objectives: To find the slope of a line given two points on the line To Find Slope Given an Equation of a Line To describe slope for horizontal and vertical lines
10 8 6 4 Slope = 2 10 6 8 -2 -4 2 4 -2 -4 -6 -8 -10 Slope run rise
10 8 6 4 Slope = 2 10 6 8 -2 -4 2 4 -2 -4 -6 -8 -10 Example 1 Graph the line containing points (2,1) and (7,6) and find the slope. run rise
Practice Graph the line containing these points and find their slopes. 1) (-2,3) (3,5) 2) (0,-3) (-3,2)
Slope = Slope or
Example 2 Find the slope of the line containing points (1,6) and (5,4).
Practice Find the slope of the lines containing these points. 2) (-2,3) (2,1) 1) (2,2) (8,9) 3) (5,-11) (-9,4)
10 8 6 4 Slope = 2 10 6 8 -2 -4 2 4 -2 -4 -6 -8 -10 Slope of a Horizontal Line What about the slope of a horizontal line? What is the rise? 0 6 What is the run? The slope of ANY horizontal line is 0.
10 8 6 4 Slope = 2 10 6 8 -2 -4 2 4 -2 -4 -6 -8 -10 Slope of a Vertical Line What about the slope of a vertical line? What is the rise? 5 0 What is the run? The slope of ANY vertical line is undefined.
10 8 6 4 Slope = 2 10 6 8 -2 -4 2 4 -2 -4 -6 -8 -10 Example 1 Find the slope of the line y = -4.
10 8 6 4 Slope = 2 10 6 8 -2 -4 2 4 -2 -4 -6 -8 -10 Example 2 Find the slope of the line x = 7. The line has no slope.
Practice Find the slopes, if they exist, of the lines containing these points. 1) (9,7) (3,7) 2) (4,-6) (4,0) 3) (2,4) (-1,5)
Slope-Intercept Equation Find the slope of the line y = 2x - 4. 8 y = 2x - 4 6 4 2 0 -4 6 8 -2 1 -2 -8 -6 -4 2 4 -2 rise: -4 2 0 -4 run: -2 -6 -8 The y-intercept is -4.
Slope-Intercept Equation y = mx + b y = 4x + 8 y = 2x - 3 slope y-intercept slope = 4 y-intercept = 8 slope = 2 y-intercept = -3
Example 1 Find the slope and y-intercept of the line y = -4x + 4. The slope is -4. The y-intercept is 4.
Example 2 Find the slope and y-intercept of the line y = 5x - 7. The slope is 5. The y-intercept is -7.
Practice Find the slope and y-intercept of each line. • y = x + 3 • y = -4x – 7 • y = 3x - 9
Example 3 Find the slope and y-intercept of the line 3x + 4y = 12. 3x + 4y = 12 solve for y -3x -3x 4y = 12 – 3x 4 4 slope y-intercept = 3
Practice Find the slope and y-intercept of each line. • y = -x - 3 2) 8x + 2y = 10 3) 3y – 6x = 12
Practice 2 Find the slope and y-intercept. • y = 3x + 4 2) y = -2x - 8 3) 2x + 7y = 9 4) 4x = 9y + 7