$\"\"$

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The expression is $\"\"$ .

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Apply cross product property: $\"\"$ when $\"\"$ .

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$\"\"$

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

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$\"\"$ (Divide each side by 7)

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$\"\"$ (Cancel common terms)

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

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The solution is $\"\"$ .