д) $$\frac{1}{8}u - 2 = \frac{5}{8}u + 1$$;

Решим уравнение:

$$\frac{1}{8}u - 2 = \frac{5}{8}u + 1$$
$$\frac{1}{8}u - \frac{5}{8}u = 1 + 2$$
$$-\frac{4}{8}u = 3$$
$$-\frac{1}{2}u = 3$$
$$u = 3 \times (-2)$$
$$u = -6$$

Ответ: -6