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The logarithm equation is $\"\"$ .

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Definition of logarithm : $\"\"$ if and only if $\"\"$ .

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$\"\"$ .

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Check logarithm equation at $\"\"$ .

Substitute $\"\"$ in $\"\"$ .

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Definition of logarithm : $\"\"$ if and only if $\"\"$ .

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The logarithm equation exist at $\"\"$ .

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The value of $\"\"$ is $\"\"$ .