$\"\"$

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The equation is $\"\"$ .

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Apply addition property of equality: If $\"\"$ then $\"\"$ .

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Add 6.7 to each side.

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$\"\"$

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$\"\"$

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$\"\"$ .

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Substitute the values of $\"\"$ in the equation $\"\"$ .

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$\"\"$

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

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The value of $\"\"$ .