[tex]\bf log_8(\sqrt[7]{64})\qquad 64=8^2\qquad log_8(\sqrt[7]{8^2})\\\\
-----------------------------\\\\
log_{{ a}}{{ a}}^x\implies x\impliedby \textit{using this cancellation rule}\\\\
-----------------------------\\\\
log_8\left( 8^{\frac{2}{7}} \right)\implies \cfrac{2}{7}[/tex]
