Adding and Subtracting Rational Expressions

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Chapter 9

• Section 5
• Adding and Subtracting Rational Expressions

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Review Problems

• Find the least common multiple of the two
  numbers.
• 7, 21 24, 10 11,17

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Add or Subtract
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Add or Subtract
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How to find the LCM/LCD(Least Common
Multiple/Denominator)

• Factor the denominator into its prime factors (as
  small as each will go).
• Write each prime factor the greatest number of
  times it appears in either expression.
• Simplify where possible.

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Find the Least Common Multiple

• 4x2 36 and 6x2 36x 54

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Find the Least Common Multiple

• 3x2 9x 30 and 6x 30

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Find the Least Common Multiple

• 5x2 15x 10 and 2x2 8

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Steps to Add/Subtract

• Factor the denominators
• Identify the LCD for multiplication
• Multiply as needed
• Add/subtract
• Simplify

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Simplify
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Simplify
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Simplify
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Simplify
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Simplify
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Homework

• Re-teaching 9.5 All

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Day Two
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Complex Fractions

• A fraction that has a fraction in its numerator
  or denominator or both
• Ex
• Two methods to simplify
• 1. Multiply everything by the LCD
• 2. Divide the numerator by the denominator

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Method 1 Multiplying by LCD

• Find the LCD of the ENTIRE fraction
• Multiply everything by this LCD (notice that the
  small fractions disappear)
• Simplify

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2. Dividing

• Simplify the numerator and denominator
• Divide the numerator by the denominator

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Homework

• Practice 9.5