$\"\"$

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The equation is $\"\"$ .

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Apply distributive property: $\"\"$ .

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$\"\"$

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$\"\"$ . $\"\"$

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Subtract 12n from each side.

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$\"\"$

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$\"\"$

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$\"\"$

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Divide each side by negative 20.

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$\"\"$

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Cancel common terms.

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$\"\"$ . $\"\"$

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The value of $\"\"$ .