Ответ:\(3^4=3\cdot3\cdot3\cdot3=81\).\(5^2=5\cdot5=25\).\(2^8=256\).\((-\frac{2}{3})^3=-\frac{2^3}{3^3}=-\frac{8}{27}\).\(0{,}8^3=0{,}8\cdot0{,}8\cdot0{,}8=0{,}512\).\((\frac{2}{5})^4=\frac{2^4}{5^4}=\frac{16}{625}\).