Решите уравнения: a + 3/14 = 8/21; x − 7/8 = 5/12.

1. \(a+\frac{3}{14}=\frac{8}{21}\).
   \(a=\frac{8}{21}-\frac{3}{14}=\frac{16}{42}-\frac{9}{42}=\frac{7}{42}=\frac{1}{6}\).
2. \(x-\frac{7}{8}=\frac{5}{12}\).
   \(x=\frac{5}{12}+\frac{7}{8}=\frac{10}{24}+\frac{21}{24}=\frac{31}{24}=1\frac{7}{24}\).

Ответ: \(a=\frac{1}{6}\); \(x=\frac{31}{24}=1\frac{7}{24}\).