Slope of a Line

• Slope


  Describes the direction of a line
• Slope


  The ratio of the change in the y-coordinates to the corresponding change in the x-coordinate
• Find the slope between two points

  1. Rise

  2. Run
• Find the slope between (-3, 6) and (5, 2)


  • Rise = -4
  • Run = 8
• The slope of a line that rises to the right is positive
• The slope of a line that rises to the left is negative
• The slope of a vertical line is undefined
• The slope of a horizontal line is 0
• Find the slope of the line 4x - y = 8


  1. Let x = 0 to find the y-intercept

  2. Let y = 0 to find the x-intercept

  3. Solve for y to get the slope-intercept form y = mx + b
• Find the slope of the line 2x + 3y = 9


  Solve for y to get the slope-intercept form
• Find the slope of the line 4y - 2x = 8


  Solve for y to get the slope-intercept form
• Find the slope of the line 10y + 2x = 20


  Solve for y to get the slope-intercept form
• Two lines with the same slope are parallel
• Two parallel lines have the same slope
• Determine if two lines are parallel


  Find the slope of each line and compare
• If neither line is vertical then the slopes of perpendicular lines are negative reciprocals
• Lines with slopes that are negative reciprocals are perpendicular
• If the product of the slopes of two lines is -1 then the lines are perpendicular

  
• Horizontal lines are perpendicular to vertical lines