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

Решение:

1. \( \frac{5}{4}z - \frac{3}{5} = \frac{7}{8} : \frac{7}{8} \)
2. \( \frac{5}{4}z - \frac{3}{5} = 1 \)
3. \( \frac{5}{4}z = 1 + \frac{3}{5} \)
4. \( \frac{5}{4}z = \frac{5+3}{5} \)
5. \( \frac{5}{4}z = \frac{8}{5} \)
6. \( z = \frac{8}{5} \cdot \frac{4}{5} \)
7. \( z = \frac{32}{25} \)

Ответ: \( z = \frac{32}{25} \).