[m]\frac{1}{3}\cdot (-\sqrt[7]{18})^7=\frac{1}{3}\cdot (-18^{\frac{7}{7}})=\frac{1}{3}\cdot (-18^{1})=\frac{1}{3}\cdot (-18)=-6[/m]
2.1
[m](2^{-0,7})^{-0,7}\cdot (0,5)^{3,49}=2^{(-0,7)\cdot (-0,7)}\cdot (2^{-1})^{3,49}=2^{0,49}\cdot 2^{-3,49}=2^{0,49+(-3,49)}=2^{-3}=\frac{1}{8}[/m]