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1.6 Slope-Intercept Form

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1.6 Slope-Intercept Form Powered By Docstoc
					Questions from 1.5 HW???
1.6
Graph Using Slope-Intercept
Form


   No School Monday: 1/18/10
   1.5-1.6 Quiz: 1/22/10
   Unit 1 Test: 1/27/10
Vocabulary
 A linear equation of the form
  y = mx + b is written in slope-
  intercept form, where m is the
  slope and b is the y-intercept of the
  equation’s graph.
              y = mx + b
                  SLOPE   y-intercept
Vocabulary
 Two lines are parallel if the do NOT
  intersect.
   Parallel lines have the SAME slope.


 Ex: y = 3x – 2 and y = 3x + 5


         Both lines have a slope
          of 3. So the lines are
                PARALLEL
                                           What is a

  Vocabulary                                negative
                                           reciprocal
                                               ??

 Two lines are perpendicular if
  they intersect to form a right
  angle.
   Perpendicular lines have slopes that
    are negative reciprocals.
 Ex: y = 2x – 3 and y = -1/2x -7


         2 and -1/2 are negative
         reciprocals. So the lines
           are PERPENDICULAR
Example 1:
 Identify the slope and y-intercept of
  the line with the given equation.
   Y = 1/4x – 2



   -2x + 3y = 9
  (what do we need to do to this equation before we can
  identify slope and the y-intercept?)
Your Turn:
 Identify the slope and y-intercept of
   the line with the given equation:
1. Y = -3x + 7
2. Y = 4x – 10
3. 15x – 5y = 10
4. Y = 5 – 7x
Example 2:
 Graph the equation 4x + y = 3 (using
  the slope and y-intercept)
Example 3:
 Determine which of the lines are
  parallel or perpendicular:
     line   a through (-4, 1) and (-6, 7)
     line   b through (-7, -5) and (1, 11)
     line   c through (2, 5) and (4, 9)
     line   d through (4, 3) and (10, 5)
**We need to find
 the slope of each
   line and then
     compare**
                              Parallel Lines:
                              have the SAME
Example 3 continued:          slope

 Find the slope of line a:
                              Perpendicular
                              Lines: have
 Find the slope of line b:   NEGATIVE
                              RECIPROCALS
                              as their slopes
 Find the slope of line c:

 Find the slope of line d:
Your Turn:
 Graph the
equation
y = 3/4x – 1
Homework:
 P. 32-33 #2-22even, 27-32

				
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posted:10/4/2011
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