$\"\"$

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The given equation is $\"\"$ .

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Rewrite the equation is $\"\"$ . $\"\"$

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First case:- $\"\"$

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Apply subtraction property of equality: Subtract 9 from each side.

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$\"\"$

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$\"\"$ (Apply additive inverse property: $\"\"$ )

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$\"\"$ (Subtract: $\"\"$ ) $\"\"$

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Second case:- $\"\"$

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Apply subtraction property of equality: Subtract 9 from each side.

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$\"\"$

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$\"\"$ (Apply additive inverse property: $\"\"$ )

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$\"\"$ (Subtract: $\"\"$ ) $\"\"$

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The value of $\"\"$ or $\"\"$ .