15 3) (-3) 5=

з) $$\left(-\frac{1}{3}\right)^5 = \left(-\frac{1}{3}\right) \cdot \left(-\frac{1}{3}\right) \cdot \left(-\frac{1}{3}\right) \cdot \left(-\frac{1}{3}\right) \cdot \left(-\frac{1}{3}\right) = -\frac{1}{243}$$

Ответ: $$\frac{-1}{243}$$