2) (0,3)⁻⁴ = (3/10)⁻⁴ = (10/3)⁴ = 10000/81 = 123 37/81;
4) (-0,7)⁻² = (-7/10)⁻² = (-10/7)² = 100/49 = 2 2/49;
6) - (-0,9)⁻² = -(-9/10)⁻² = -(-10/9)² = -100/81 = -1 19/81;
8) (2,1)⁻² = (21/10)⁻² = (10/21)² = 100/441.
Ответ: