б) \(\frac{8}{9} \times \frac{3}{4} - \frac{1}{14} : \frac{2}{7}\)

Решение:

1. \(\frac{8}{9} \times \frac{3}{4} = \frac{8 \times 3}{9 \times 4} = \frac{24}{36} = \frac{2}{3}\)
2. \(\frac{1}{14} : \frac{2}{7} = \frac{1}{14} \times \frac{7}{2} = \frac{7}{28} = \frac{1}{4}\)
3. \(\frac{2}{3} - \frac{1}{4} = \frac{2 \times 4 - 1 \times 3}{12} = \frac{8-3}{12} = \frac{5}{12}\)

Ответ: \(\frac{5}{12}\)