Log7log7√7(√7√7)

Start from the most complex root over root...
As the base is same, assign each ‘7’ their individual powers to which they are raised. If a specific base is assigned, for instance base 7, sum the power, bring the power in multiplication with the log7(in the interior of first log). Proceed to get a simplifoed solution as the log₇7 will be 1 and log1 will be 0.