Algebra A

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Algebra A

• Chapter 7 Linear Equations
• 7-7 Parallel and Perpendicular Lines
• Page 323

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7-7 Parallel and Perpendicular Lines

• WARMUP
• Given the following line y 3x 2
• Change this equation so that the line is steeper.
• Change this line so that the new line does not
  intersect the original line
• Change this line so that it is perpendicular to
  the original.

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7-7 Parallel and Perpendicular Lines

• GOAL
• To work with parallel and perpendicular lines.
• To recognize Families of Graphs.

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7-7 Parallel and Perpendicular Lines

• Section 7-6 A family of graphs is a collection
  of graphs that have at least one characteristic
  in common. For example
• Parallel lines are a Family of Graphs.

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7-7 Parallel and Perpendicular Lines

• Lines with the same y-intercept are also a family
  of graphs.

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7-7 Parallel and Perpendicular Lines

• Lines with different slopes and different
  intercepts are NOT a family of graphs.

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7-7 Parallel and Perpendicular Lines

• Are the following sets of lines a family of
  graphs?
• a. y 3x 3
• b. y -12x 3
• a. y 3x 2
• b. y 2x 2

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7-7 Parallel and Perpendicular Lines

• Investigate Parent Graphs and how changes will
  affect lines

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7-7 Parallel and Perpendicular Lines

• Lines that have the same slope are parallel.
• In this example, we
• would write

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7-7 Parallel and Perpendicular Lines

• Please write down three lines that are parallel
  to
• y -2x 2

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7-7 Parallel and Perpendicular Lines

• Closely examine example 2 on page 323.

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7-7 Parallel and Perpendicular Lines

• The slopes of perpendicular lines are the
  negative reciprocals of each other.
• OR
• If the product of the slopes of two lines is -1,
  then the lines are perpendicular.

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7-7 Parallel and Perpendicular Lines

• Are these lines perpendicular?
• y x 2
• y -x 2

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7-7 Parallel and Perpendicular Lines

• More examples.

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7-7 Parallel and Perpendicular Lines

• Homework