\(=\left[\left(6+\dfrac{3}{5}-3-\dfrac{3}{14}\right)\cdot\dfrac{35}{6}\right]:\left[19.75:2.5\right]\)
\(=\left[\left(3+\dfrac{27}{70}\right)\cdot\dfrac{35}{6}\right]:\dfrac{79}{10}\)
\(=\dfrac{97}{70}\cdot\dfrac{35}{6}\cdot\dfrac{10}{79}=\dfrac{485}{474}\)