Adding and Subtracting Rational Expressions with Different Denominators
Example 1
Find:
Solution
Step 1 Find the LCD. |
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Factor each denominator.
|
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The LCD is w(w - 6)
· 2
· 2
· y. |
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Step 2 Rewrite each
rational expression
with the LCD as
the denominator. |
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Step 3 Add (or subtract) the numerators.
The denominator stays the same. |
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Subtract the numerators. |
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Distribute the -7. |
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Step 4 Reduce to lowest terms. |
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The numerator cannot be factored using integers. Since there are no
factors, other than 1 or -1, common to the numerator and denominator,
the expression is in lowest terms.So,
Example 2
Find:
Solution
Step 1 Find the LCD. |
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Factor each denominator.
|
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The LCD is (x - 3)(x
- 3)(x + 3). |
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Step 2 Rewrite each rational expression
with the LCD as the denominator. |
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Step 3 Add (or subtract) the numerators. The denominator stays the
same. |
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Subtract the numerators. |
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In the numerator,
distribute the x and the -3. |
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Combine like terms. |
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Step 4 Reduce to lowest terms. |
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The numerator cannot be factored over the integers.
Since there are no factors, other than 1 or -1, common to the numerator
and the denominator, the expression is in lowest terms.
So,
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