26) (1/5)⁻⁴ : (1/5)⁻⁶ =

\(\left(\frac15\right)^{-4}:\left(\frac15\right)^{-6}=\left(\frac15\right)^{-4-(-6)}=\left(\frac15\right)^2=\frac{1}{25}\).

Ответ: \(\frac{1}{25}\).