Section 6'3 Addition and Subtraction of Rational Expressions

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Section 6.3 Addition and Subtraction of Rational
Expressions

• Page 371

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Example 1
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Example 2
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Adding Rational Expressions

• If P/Q and R/Q are rational expressions, then

The denominators must be the same.
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Definition LCDLeast Common Denominator

• The least common denominator for a set of
  denominators is the simplest quantity that is
  exactly divisible by all denominators.

10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110,
120, 130, 140
14, 28, 42, 56, 70, 84, 98, 112, 126, 140
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Example 3
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Adding Rational Expressions with Different
Denominators

• Find the least common denominator.
• Rewrite each rational expression as an equivalent
  fraction with the least common denominator as the
  denominator.
• Add the numerator to get the numerator sum. The
  least common denominator is the denominator of
  the sum.
• Write the answer in lowest terms.

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Find the Least Common Denominator
First factor the denominators.
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Rewrite each rational expression as an equivalent
fraction with the least common denominator as the
denominator.
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Add the numerator to get the numerator sum. The
least common denominator is the denominator of
the sum.
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Finally write the answer in lowest terms.
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Example D

• Find the least common denominator.

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Example D

• Rewrite each rational expression as an equivalent
  fraction with the least common denominator as the
  denominator.

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Example D

• Add the numerators to get the numerator sum. The
  least common denominator is the denominator of
  the sum.

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(No Transcript)
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Write the answer in lowest terms.

• This one has a prime numerator, so it will not
  reduce.

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Subtraction is just about the same.(Except for
where it is different)
Danger
Danger
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Subtraction is just about the same.
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Subtraction is just about the same.
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