\"\"

\

The expression is \"\"

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\"\"   (Product of two same signs is positive)

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\"\"   (\"\")

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\"\"   (\"\")\"\"

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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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\"\"

\

\"\"

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The product is \"\".