\(\dfrac{7}{20}:\left(\dfrac{5}{2}-\dfrac{7}{20}\right):\dfrac{86}{5}-\dfrac{7}{8}\left(\dfrac{4}{5}-\dfrac{8}{7}\right)-\left(1+\dfrac{7}{12}-\dfrac{4}{3}\right)\)
\(=\dfrac{7}{20}:\left(\dfrac{50}{20}-\dfrac{7}{20}\right):\dfrac{86}{5}-\dfrac{7}{8}\left(\dfrac{28}{35}-\dfrac{40}{35}\right)-\left(\dfrac{12}{12}+\dfrac{7}{12}-\dfrac{16}{12}\right)\)
\(=\dfrac{7}{20}:\dfrac{43}{20}:\dfrac{86}{5}-\dfrac{7}{8}.\left(-\dfrac{12}{35}\right)-\dfrac{1}{4}\)
\(=\dfrac{7}{43}:\dfrac{86}{5}+\dfrac{3}{10}-\dfrac{1}{4}\)
\(=\dfrac{14}{5}+\dfrac{3}{10}-\dfrac{1}{4}\)
\(=\dfrac{56}{20}+\dfrac{6}{20}-\dfrac{5}{20}\)
\(=\dfrac{57}{20}\)
\(\dfrac{7}{20}:\left(\dfrac{5}{2}-\dfrac{7}{20}\right):\dfrac{86}{5}-\dfrac{7}{8}\left(\dfrac{4}{5}-\dfrac{8}{7}\right)-\left(1+\dfrac{7}{12}-\dfrac{4}{3}\right)\)
\(=\dfrac{7}{20}:\left(\dfrac{50}{20}-\dfrac{7}{20}\right):\dfrac{86}{5}-\dfrac{7}{8}\left(\dfrac{28}{35}-\dfrac{40}{35}\right)-\left(\dfrac{12}{12}+\dfrac{7}{12}-\dfrac{16}{12}\right)\)
\(=\dfrac{7}{20}:\dfrac{43}{20}:\dfrac{86}{5}-\dfrac{7}{8}.\left(-\dfrac{12}{35}\right)-\dfrac{1}{4}\)
\(=\dfrac{7}{43}.\dfrac{5}{86}+\dfrac{3}{10}-\dfrac{1}{4}\)
\(=\dfrac{35}{3698}+\dfrac{3}{10}-\dfrac{1}{4}\)
\(=\dfrac{2199}{36980}\)