\(\left[\left(\frac{33}{5}-\frac{45}{14}\right).\frac{35}{6}\right]:\left[\left(21-1,25\right):2,5\right]\)
\(=\left[\left(\frac{462}{70}-\frac{225}{70}\right).\frac{35}{6}\right]:\left[19,75:2,5\right]\)
\(=\left[\frac{237}{70}.\frac{35}{6}\right]:7,9\)
\(=\frac{79}{4}:\frac{79}{10}\)
\(=\frac{79}{4}.\frac{10}{79}\)
\(=\frac{5}{2}\)