Do Now 11/2/09

1
Do Now 11/2/09

• Take out HW from Friday.
• Practice worksheet 4.4 form C evens
• Copy HW in your planner.
• Text p.247 4-38 even
• Be ready for slope quiz.

2
Homework Practice worksheet 4.4 Form C

• 2) undefined
• 4) zero
• 6) positive
• 8) -11/6
• 10) 4/3
• 12) 0
• 14) -2/3
• 16) 3/5
• 18) undefined
• 20) 4/7
• 22) 0

• 24) 1/6
• 26) -7
• 28) -1
• 30) -4
• 32) a) From 1996 to 1998. b) From 1996 to 1998.
  c) Overall, the slope of both lines is positive
  meaning that fuel consumption has increased over
  the 10 year period.

3
Objective

• SWBAT graph linear equations using
  slope-intercept form

4
Slope Review

• The slope m of a line passing through two points
• and is the ratio of
  the rise change to the run.

y
run
rise
x
5
Section 4.5 Graph Using Slope-Intercept Form

• SLOPE-INTERCEPT FORM-
• a linear equation written in the form

y-coordinate
x-coordinate
y mx b
slope
y-intercept
6
Identifying Slope and the Y-Intercept
Slope of 3 means
y mx b
Is this in slope-intercept form?
7
Identify the slope and y-intercept of the line
with the given equation.
Rewrite the equation in slope-intercept form by
solving for y.
Rewrite original equation.
Divide 3 by equation.
Simplify.
8
Graph an Equation Using the Slope-Intercept Form
Graph the equation y 2 - 2x.
y-axis
5
4
Rewrite in slope-intercept form
3
2
1
slope
y-intercept
0
1
2
3
4
5
6
-6
-5
-4
-3
-2
-1
x-axis
-1
Slope of -2 means
-2
OR
-3
Slope of -2 means
-4
-5
9
Graph an Equation Using the Slope-Intercept Form
Graph the equation y -3 2/3x.
y-axis
5
4
Rewrite in slope-intercept form
3
2
1
slope
y-intercept
0
1
2
3
4
5
6
-6
-5
-4
-3
-2
-1
x-axis
-1
Slope of 2/3 means
-2
OR
-3
Slope of 2/3 means
-4
-5
10
Graph Using Slope and the Y-Intercept
Graph the equation 2x y 3.
STEP 1
Slope of -2 means
Rewrite the equation in slope-intercept form.
STEP 2
Identify the slope and the y-intercept.
STEP 3
Plot the point that corresponds to the
y-intercept,(0, 3).
STEP 4
Use the slope to locate a second point on the
line. Draw a line through the two points.
11
Graph Using Slope and the Y-Intercept
Graph the equation 3y 2x 3.
Slope of 2/3 means
STEP 1
Rewrite the equation in slope-intercept form.
STEP 2
Identify the slope and the y-intercept.
STEP 3
Plot the point that corresponds to the
y-intercept,(0, 1).
STEP 4
Use the slope to locate a second point on the
line. Draw a line through the two points.
12
Parallel Lines

• two lines in the same plane are parallel if
  they never intersect. Because slope gives the
  rate at which a line rises or falls, two lines
  with the SAME SLOPE are PARALLEL.

13
Determine which of the lines are parallel.
Find the slope of each line.
Line a m
Line b m
Line c m
14
HomeworkText p.247 4-38 even
24
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HomeworkPractice Form C evens

• 2) slope -6 y-int 19
• 4) slope -3/2 y-int 4
• 6) slope 4/3 y-int 3
• 8) slope 4/9 y-int -2
• 10 18) on overhead
• 20) line through (-1,3) and (0,-3) and line
  through (0,2) and (1,-4) both have slopes of -6
• 22) parallel slopes of 0.5
• 24) -38
• 26) -2
• 28) 6 the cost increases by 2 per hour

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Practice Form B2-22 even

• 16) overhead
• 18) overhead
• 20) overhead
• 22) line through (-1,-4) and (0,2) and line
  through (1,3) and (2,9)
• 24) no
• 26) no
• 28) yes
• 30) ab) overhead c) 12

• 2) slope -4 y-int 10
• 4) slope -4 y-int 3
• 6) slope -2/5 y-int 2
• 8) slope -3/2 y-int ½
• 10) slope -1 y-int 3/5
• 12) slope undefined y-int none
• 14) B