$\"\"$

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The expression is $\"\"$ .

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$\"\"$ (Substitute $\"\"$ ) $\"\"$

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if $\"\"$ ,where b,d $\"\"$

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$\"\"$

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$\"\"$ (Cancel common terms)

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$\"\"$ (Multiply numerators: $\"\"$ )

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$\"\"$ (Multiply denominators: $\"\"$ ) $\"\"$

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The product is $\"\"$ .