4. Решите уравнение: (3 1/2 +(2/3)²)⋅x+3/18=5/18.

$$(\frac{7}{2} + (\frac{2}{3})^2) \cdot x + \frac{3}{18} = \frac{5}{18}$$

$$(\frac{7}{2} + \frac{4}{9}) \cdot x + \frac{3}{18} = \frac{5}{18}$$

$$(\frac{7 \cdot 9 + 4 \cdot 2}{18}) \cdot x + \frac{3}{18} = \frac{5}{18}$$

$$\frac{63+8}{18} \cdot x = \frac{5}{18} - \frac{3}{18}$$

$$\frac{71}{18} \cdot x = \frac{2}{18}$$

$$x = \frac{2}{18} : \frac{71}{18}$$

$$x = \frac{2}{18} \cdot \frac{18}{71}$$

$$x = \frac{2}{71}$$

Ответ: $$\frac{2}{71}$$