3(2 – i)∙(1 – i); (1 + 3i)(–7 + 2i); (2 – i)2; (1 + 2i)3.

Вычислим значение выражения:

1) 3 * (2 – i) * (1 – i) =  3 * (2 * 1 - 2 * i - 1 * i + i * i) = 3 * (2 - 2 * i - i + i^2) = 3 * (2 - 3 * i - 1) = 3 * (-3 * i + 1) = 3 - 9 * i;

2) (1 + 3 * i) * (–7 + 2 * i) = -7 * 1 + 2 * i * 1 - 3 * 7 * i + 3 * 2 * i * i = -7 + 2 * i - 21 * i + 6 * i^2 = -7 - 19  * i - 6 * 1 = -19 * i - 13; 

3) (2 – i)^2 = 2^2 - 2 * 2 * i + i^2 = 4 - 4 * i + i^2 = 4 - 4 * i - 1 = -4 * i + 3 = 3 - 4 * i;

4) (1 + 2 * i)^3 = 1^3 + 3 * 1^2 * 2 * i + 3 * 1 * 2^2 * i^2 + (2 * i)^3 = 1 + 6 * i + 12 * i^2 + 8 * i^3 = 1 + 6 * i - 12 + 8 * i^2 * i = 6 * i - 11 - 8 * i = -2 * i - 11.