\[\left( \frac{28}{31} + x \right) - \frac{14}{31} = \frac{16}{31}\]
\[\frac{28}{31} + x = \frac{16}{31} + \frac{14}{31}\]
\[\frac{28}{31} + x = \frac{30}{31}\]
\[x = \frac{30}{31} - \frac{28}{31}\]
\[x = \frac{2}{31}.\]