谜题/算术谜题/对数谜题/对数谜题 1 解答

谜题 | 算术谜题 | 对数谜题 | 对数谜题 1 解答

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${777 \over 121}:{\operatorname {log} _{\sqrt {\sqrt {\sqrt {\sqrt {\sqrt {\sqrt {\sqrt {7}}}}}}}}7}-7$