$\"\"$

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The equation is $\"\"$ .

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Apply formulas : $\"\"$

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$\"\"$

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Cancel common terms.

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$\"\"$

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Add $\"\"$ to each side.

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$\"\"$

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$\"\"$ \ \

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Subtract 9 from each side.

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$\"\"$

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$\"\"$

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Divide each side by 20.

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$\"\"$

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$\"\"$ .

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$\"\"$

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The value of $\"\"$ .