$\"\"$

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The values are $\"\"$ .

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Apply sum of an arithmetic series formula: $\"\"$ .

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$\"\"$ (Substitute $\"\"$ )

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

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

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

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Apply division property of equality: a = b then $\"\"$ .

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$\"\"$ (Divide each side by 6)

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$\"\"$ (Cancel common terms)

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

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Apply addition property of equality: a = b then $\"\"$ .

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$\"\"$ (Add 22 to each side)

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$\"\"$ (Add: 16 + 22 = 38)

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Apply division property of equality: a = b then $\"\"$ .

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$\"\"$ (Divide each side by 2)

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$\"\"$ (Cancel common terms)

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

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The value of $\"\"$ .