\(2.\dfrac{1}{5}:\dfrac{3}{10}+\dfrac{5}{6}.\left(\dfrac{12}{5}-\dfrac{6}{25}+\dfrac{18}{75}\right)-\dfrac{18}{17}:\dfrac{9}{34}\)
\(=\dfrac{1}{5}.\dfrac{10}{3}+\dfrac{5}{6}.\left(\dfrac{60-6+6}{25}\right)-\dfrac{18}{17}.\dfrac{34}{9}\)
\(=\dfrac{2}{3}+\dfrac{5}{6}.\dfrac{12}{5}-4\)
\(=-\dfrac{4}{3}\)