5) (1/2)^2 = (1/2) * (1/2) = 1/4
6) (-1/2)^3 = (-1/2) * (-1/2) * (-1/2) = -1/8
7) (-1/2)^4 = (-1/2) * (-1/2) * (-1/2) * (-1/2) = 1/16
8) (-1/2)^3 = (-1/2) * (-1/2) * (-1/2) = -1/8
9) (-2/3)^2 = (-2/3) * (-2/3) = 4/9
Ответы: 5) 1/4; 6) -1/8; 7) 1/16; 8) -1/8; 9) 4/9