$\"\"$

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The equation is $\"\"$ .

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$\"\"$ (Add 9 to each side)

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$\"\"$ (Apply commutative property: $\"\"$ )

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

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

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$\"\"$ (Add: $\"\"$ ) $\"\"$

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$\"\"$ (Multiply each side by negative one)

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

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$\"\"$ (Product of two different signs is negative) $\"\"$

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Check:

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To check the solution, substitute $\"\"$ in original equation.

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$\"\"$

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

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$\"\"$ (Add: $\"\"$ )

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The statement is true. $\"\"$

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The value of $\"\"$ .