$\"\"$

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The given values $\"\"$ .

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Where $\"\"$ is the first term and $\"\"$ is the common difference.

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The sum of an arithmetic series $\"\"$ .

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

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

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

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

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$\"\"$ (Cancel common term)

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

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

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$\"\"$ (Divide each side by 121)

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$\"\"$ (Cancel common term)

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

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Apply nth term of the arithmetic sequence formula: $\"\"$ .

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

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

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

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$\"\"$ (Subtract 11 from each side)

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

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$\"\"$ (Divide each side by 11)

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$\"\"$ (Cancel common terms)

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d = 9 (Divide: $\"\"$ )

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The 1st term is $\"\"$ , 2nd term is $\"\"$

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3rd term is $\"\"$ $\"\"$

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The first three terms of the arithmetic series is 11, 20, and 29.