$\"\"$

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The given sequence $\"\"$ .

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$\"\"$

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Apply nth term of a geometric sequence formula $\"\"$ .

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

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

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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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$\"\"$ (Rewrite $\"\"$ )

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$\"\"$ (Apply equal powers formula: $\"\"$ ) $\"\"$

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Apply 2nd term of a geometric sequence formula $\"\"$ .

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

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

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Apply 3nd term of a geometric sequence formula $\"\"$ .

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

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

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The geometric means are 6, 18.