$\"\"$

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The equation is $\"\"$ .

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Apply subtraction property of equality: Subtract 15 from each side.

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$\"\"$

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

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

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

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$\"\"$ (Multiply each side by negative 3)

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$\"\"$ (Cancel common terms)

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

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$\"\"$ (Multiply: $\"\"$ ) $\"\"$

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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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$\"\"$ (Divide: $\"\"$ )

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

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The value of $\"\"$ .