39) \(-\frac{1}{125}b^6c^6=\)

\(-\frac{1}{125}=\left(-\frac{1}{5}\right)^3\), а \(b^6=(b^2)^3\), \(c^6=(c^2)^3\).

\(-\frac{1}{125}b^6c^6=\left(-\frac{b^2c^2}{5}\right)^3\).

Ответ: \(\left(-\frac{b^2c^2}{5}\right)^3\).