1. Section 3.1
Graphs of Linear Equations

2. OBJECTIVES Graph (plot) ordered pairs of numbers.
Determine the coordinates of a point in the plane. B

3. OBJECTIVES Read and interpret ordered pairs on a line graph.
Read and interpret ordered pairs on a bar graph. D

4. OBJECTIVES Find the quadrant in which a point lies.
Given a chart or ordered pairs, make a line graph. F

5. RULES (x, y) x-coordinate y-coordinate Tells us go right or left
Tells us to go up or down

6. (x,y) SIGNS BY QUADRANT II I
(-,+)
(+,+)
III IV
(-,-)
(+,-)

7. Section 3.1 Exercise #1 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

9. Section 3.1 Exercise #2 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

11. Section 3.1 Exercise #3 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

12. Wind Chill Temperature Comparison
Wind Speed (mph)
Wind chill temperature (°F)
Old wind chill formula
New wind chill formula

13. Wind Chill Temperature Comparison
Wind Speed (mph)
Wind chill temperature (°F)
Old wind chill formula
New wind chill formula

14. Wind Chill Temperature Comparison
Wind Speed (mph)
Wind chill temperature (°F)
Old wind chill formula
New wind chill formula

15. Wind Chill Temperature Comparison
Wind Speed (mph)
Wind chill temperature (°F)
Old wind chill formula
New wind chill formula

16. Wind Chill Temperature Comparison
Wind Speed (mph)
Wind chill temperature (°F)
Old wind chill formula
New wind chill formula

17. Wind Chill Temperature Comparison
Wind Speed (mph)
Wind chill temperature (°F)
Old wind chill formula
New wind chill formula

18. Wind Chill Temperature Comparison
Wind Speed (mph)
Wind chill temperature (°F)
Old wind chill formula
New wind chill formula

19. Section 3.1 Exercise #4 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

20. Length of loan (in months)
Monthly payment (in dollars)

21. What is the monthly payment if you want to pay off the loan in:
Length of loan (in months)
Monthly payment (in dollars)

22. What is the monthly payment if you want to pay off the loan in:
Length of loan (in months)
Monthly payment (in dollars)

23. What is the monthly payment if you want to pay off the loan in:
Length of loan (in months)
Monthly payment (in dollars)

24. Section 3.1 Exercise #5 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

25. Determine the quadrant in which each of the points is located:

26. Determine the quadrant in which each of the points is located:

27. Determine the quadrant in which each of the points is located:

28. Determine the quadrant in which each of the points is located:

29. Section 3.1 Exercise #6 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

30. The ordered pairs represent the old wind chill temperature in degrees Fahrenheit when the wind speed in miles per hour is as indicated.
Wind speed
Wind chill
Wind Speed
Wind Chill

31. Wind speed
Wind chill
Wind Speed
Wind Chill

32. Wind speed
Wind chill
Wind Speed
Wind Chill

33. Wind speed
Wind chill
Wind Speed
Wind Chill

34. Section 3.2
Graphs of Linear Equations

35. OBJECTIVES
Determine whether a given ordered pair is a solution of an equation. A

36. OBJECTIVES Find ordered pairs that are solutions of a given equation.

37. OBJECTIVES
Graph linear equations of the forms C

38. OBJECTIVES
Solve applications involving linear equations. D

39. PROCEDURE Graphing lines
Choose a value for one variable, calculate the value of the other variable, graph the resulting ordered pair.

40. PROCEDURE Graphing lines
Repeat step 1 to obtain at least two ordered pairs.

41. PROCEDURE Graphing lines
Graph the ordered pairs and draw a line passing through the points.

42. RULE
Straight-Line Graphs
The graph of a linear equation of the form:

43. Not Linear

44. 5 –5 5 –5

45. 5 -5 5 -5

46. 5 -5 5 -5

47. Section 3.2 Exercise #7 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

48. No

49. Section 3.2 Exercise #8 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

50. In (x, 2), y = 2 so 3x – y = 10
becomes: 3x – 2 = 10
add 2: x = 12
divide by 3: x = 4

51. Section 3.2 Exercise #9 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

54. Section 3.2 Exercise #10 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

57. Section 3.2 Exercise #11 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

59. Section 3.3
Graphs of Linear Equations

60. OBJECTIVES
Graph lines using intercepts. A

61. OBJECTIVES
Graph lines passing through the origin. B

62. OBJECTIVES
Graph horizontal and vertical lines. C

63. OBJECTIVES
Solve applications involving graphs of lines. D

64. PROCEDURE x- and y- intercepts
The x-intercept (a, 0) is the point at which the line crosses the x-axis. To find the x-intercept, let y = 0 and solve for x.

65. PROCEDURE x- and y- intercepts
The y-intercept (0, b) is the point at which the line crosses the y-axis. To find the y-intercept, let x = 0 and solve for y.

66. PROCEDURE Graph a Line Using Intercepts Find the x-intercept (a, 0)
Find the y-intercept (0, b)

67. PROCEDURE Graph a Line Using Intercepts
Graph (a, 0) and (0, b), then connect them with a line.
Find a third point to use as a check.

68. PROCEDURE Graphing Lines Through the Origin.
Use the point (0, 0), and another point, then draw the line passing through both. Verify with a third point.

69. NOTE
y = k
is a horizontal line crossing the y-axis at k.

70. NOTE
x = k
is a vertical line crossing the x-axis at k.

71. Section 3.3 Exercise #12 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

75. Section 3.3 Exercise #13 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

78. Section 3.3 Exercise #14 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

80. Vertical line

81. Section 3.3 Exercise #15 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

82. Horizontal line

83. Section 3.4
Graphs of Linear Equations

84. OBJECTIVES
Find the slope of a line given two points. A

85. OBJECTIVES
Find the slope of a line given the equation of the line. B

86. OBJECTIVES
Determine whether two lines are parallel, perpendicular, or neither. C

87. OBJECTIVES
Solve an application. D

88. DEFINITION
SLOPE

89. DEFINITION
SLOPE

90. NOTE SLOPE OF y = mx + b The slope of the line defined by the equation
y = mx + b is m.

91. PROCEDURE Finding a Slope. Solve the equation for y.
The slope is m, the coefficient of x.

92. DEFINITION Slopes of Parallel and Perpendicular Lines
Two lines with the same slope but different y-intercepts are parallel.

93. DEFINITION Slopes of Parallel and Perpendicular Lines
Two lines whose slopes have a product of –1 are perpendicular.

94. Section 3.4 Exercise #16 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

95. Find the slope of the line going through:

96. Find the slope of the line going through:

97. Find the slope of the line going through:

98. Section 3.4 Exercise #17 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

99. Find the slope of the line going through:

100. Find the slope of the line going through:
Undefined

101. Find the slope of the line going through:

102. Section 3.4 Exercise #18 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

103. slope

104. Section 3.4 Exercise #19 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

105. Decide whether the lines are parallel, perpendicular or neither.

106. Decide whether the lines are parallel, perpendicular or neither.

107. Decide whether the lines are parallel, perpendicular or neither.

108. Decide whether the lines are parallel, perpendicular or neither.
and

109. Section 3.4 Exercise #20 Chapter 3 Graphs of Linear Equations
Let’s work Exercise #19 from Section 5.1

110. The number N of stores in a city t years after 2000 can be approximated by
Annual increase in the number of stores