$\"\"$ $\"\"$

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The equation is $\"\"$

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

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According to subtraction property of equality: If a = b then $\"\"$ \ \

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$\"\"$ (Subtract 18 from each side)

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$\"\"$ (Commutative property: $\"\"$ )

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$\"\"$ (Additive inverse property: $\"\"$ )

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

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Verify:

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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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Compare the values, the equation is true.

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$\"\"$

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The value of $\"\"$