Perkalian berulang dari 7 pangkat negatif 4

[tex]7 ^{-4}= \frac{1}{7}\times \frac{1}{7}\times \frac{1}{7}\times \frac{1}{7} = \frac{1}{49}\times \frac{1}{7}\times \frac{1}{7} = \frac{1}{343}\times \frac{1}{7}= \bold{\frac{1}{2401} }[/tex]