Я квадрат и куб буду писать через ^. m^2 - это m в квадрате.
а) m^2 - 2/3.
m = -1; m^2 - 2/3 = (-1)^2 - 2/3 = 1 - 2/3 = 1/3
m = -2/9; m^2 - 2/3 = (-2/9)^2 - 2/3 = 4/81 - 2/3 = 4/81 - 54/81 = -50/81
b) 2 - x^3
x = -1; 2 - (-1)^3 = 2 - (-1) = 3
x = 0,5; 2 - x^3 = 2 - (0,5)^3 = 2 - 0,125 = 1,875
x = -2/3; 2 - x^3 = 2 - (-2/3)^3 = 2 - (-8/27) = 2 8/27 = 62/27