Warmup

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Warmup

• Find LCM

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Review (LCM)

• What is the LCM of the following numbers?
• 8x²y² and 12xy³
• Other examples

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Even if it is a factor

• What is LCM of (x-1) and x²-1
• Note Factor it first!
• LCM is one of each factorif there are two of the
  same in one group, its both
• What that means
• What is LCM of 2x-10 and 6x-30
• y² 5y4, y² 2y 1

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What is the LCM?

• x² 5x 6 and x² - 1
• Factor
• (x 6)(x 1) and (x-1)(x1)
• LCM is (x-6)(x1)(x-1)
• x² 4 and x 1
• (cannot factor, so LCM is their products)

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Examples

• Find LCM (from practice masters page 36. 7-12)

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Nowto actually do the problems

• We have been working on finding the LCM of sets
  of problems.
• Now we will use this to actually add or subtract
  rational expressions with unlike denominators

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The problems

• Step One Find the LCM
• Step Two Multiply to create a common
  denominator
• Step Three Add or Subtract
• Step Four Simplify the top. Make sure to
  multiply everything out and combine like terms!
  Thencan anything cross out? Do you need to
  factor?

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Step by Step Examples
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Whiteboard Practice

• Use page 36 in practice masters (13-24)

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Classwork Assignment

• Reteaching Masters. Page 83.
• Complete 7-12

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Homework

• Quiz Wednesday on add/subtr unlike denominators!
• HW5
• p448. 1-18