15 x = 100, solve for x.

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1. 15 x 100, solve for x.
2. Given the data below, what is the probability
   that a person will buy a bicycle rather than a
   scooter.
3. x 30 -50, solve for x
4. Round the given number to the hundredths place,
   215.6977
5. Round the given number to the ones place,
   215.6977

  Person A Person B Person C Person D Person E
Scooter x   x x  
Bicycle   x     x
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Graphing Activity

• Get into groups of 2-3 students.
• Each group will get a starting point and a slope
• Your task is to find the next point in your line
• Then check your point by finding the slope
  between the starting point and your point

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Standard Formx- and y-intercepts

• November 28/29, 2011

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What is a Linear Equation?

• In a graph, Linear equations will be a line
• In a table, Linear equations will have an
  arithmetic pattern
• In an equation, Linear equations can be written
  as slope-intercept form, y mx b, and standard
  form, Ax By C

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Standard Form

• To be a linear equation, an equation must be able
  to be written in the form Ax By C
• This is called Standard Form
• A, B and C are always integers (no fractions)
• A must be positive
• Is this in Standard Form?
• 3x 5y 12
• 1/2x y 12
• -2x 5y 30

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How to change an equation to Standard Form

• Write ?x 6y 1 in standard form.
• Identify A, B, and C.
• ?x 6y 1 Original equation
• 6y 6y___ Add 6y to each side.
• ?x 6y 1
• 3(?x 6y 1) Multiply each side by 3
• 2x 18y 3
• So, A 2, B 18, and C 3.

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Example 2

• Put 2 5y x in Standard form and identify A,
  B and C.
• 2 5y x Original equation
• 2 5y x Add x to each side.
• x x
• 2 5y x 0 Subtract 2 from each side.
• 2 5y x 0
• 2 2
• x 5y 2 Simplify.  
• A 1, B 5, and C 2.

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Now You Try

• Can this be written in Standard Form?
• If yes, change to Standard Form.
• y 2x 5
• 7x 4y 6
• y x² 6
• ¾x ½y 12

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Practice

• Work on problems 1-9
• You have 15 minutes.

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Finding x- and y-intercepts

• x-intercept
• where a line crosses the x-axis
• when y 0
• (x, 0)
• y-intercept
• where a line crosses the y-axis
• when x 0
• (0, y)

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Finding the x-intercepts and y-intercepts
(continued)

• Which is the intercepts?
• A x-intercept is 0 y-intercept is 6.
• B x-intercept is 3 y-intercept is 0.
• C x-intercept is 3 y-intercept 6.
• D x-intercept is 6 y-intercept is 3.

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Graphing using x-intercepts and y-intercepts
Graph 5x y 10 using the x- and y-intercepts.

• To find the y-intercept,
• let x 0.
• 5x y 10 Original
• Replace x with 0.
• 5(0) y 10 Simplify.
• y 10 Multiply each side by 1.
• y 10
• y-intercept is (0, -10)

• To find the x-intercept,
• let y 0
• 5x y 10 Original
• Replace y with 0.
• 5x 0 10 Simplify.
• 5x 10
• Divide each side by 5.
• x 2
• x-intercept is (2, 0)

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Finding x- and y-interceptsNow you try

• y 3x -1
• 5x 3y 15
• x 4y -8

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Finding x- and y-interceptsNow you try
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Practice

• Work on problems 10-18
• You have 15 minutes