г) (\frac{5}{4}z - \frac{3}{5}) \cdot \frac{7}{8} = \frac{7}{8}.

г) Решим уравнение:

$$(\frac{5}{4}z - \frac{3}{5}) \cdot \frac{7}{8} = \frac{7}{8}$$

$$\frac{5}{4}z - \frac{3}{5} = \frac{7}{8} : \frac{7}{8}$$

$$\frac{5}{4}z - \frac{3}{5} = 1$$

$$\frac{5}{4}z = 1 + \frac{3}{5}$$

$$\frac{5}{4}z = \frac{5}{5} + \frac{3}{5}$$

$$\frac{5}{4}z = \frac{8}{5}$$

$$z = \frac{8}{5} : \frac{5}{4}$$

$$z = \frac{8}{5} \cdot \frac{4}{5}$$

$$z = \frac{32}{25} = 1\frac{7}{25}$$

Ответ: $$1\frac{7}{25}$$