$\"\"$

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The logarithmic expression is $\"\"$ .

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(a)

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Changing of base using common logarithms : $\"\"$ .

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$\"\"$ .

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$\"\"$

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(b)

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Changing of base using natural logarithms : $\"\"$ .

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$\"\"$ . $\"\"$

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(a) $\"\"$ .

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(b) $\"\"$ .