$\"\"$

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The first term is $\"\"$ and $\"\"$ .

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$\"\"$ (Substitute k = 1)

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

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$\"\"$ (Simplify)

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$\"\"$ (Apply common ratio formula: $\"\"$ ) $\"\"$

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(Apply nth term of a geometric sequence formula: $\"\"$ )

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$\"\"$ (1st term)

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$\"\"$ (2nd term)

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$\"\"$ (3rd term)

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$\"\"$ (Simplify) $\"\"$

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$\"\"$ (4th term)

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$\"\"$ (Simplify)

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$\"\"$ (5th term)

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$\"\"$ (Simplify) $\"\"$

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The first five terms of the geometric sequence is 81, 27, 9, 3, 1.