Bài 2
a) \(\dfrac{11}{8}.\left[\left(\dfrac{-5}{11}:\dfrac{13}{8}-\dfrac{5}{11}:\dfrac{13}{5}\right)+\dfrac{-6}{33}\right]+\dfrac{-3}{4}\)
\(=\dfrac{11}{8}\left[\left(\dfrac{-5}{11}.\dfrac{8}{13}-\dfrac{5}{11}.\dfrac{5}{13}\right)-\dfrac{6}{33}\right]-\dfrac{3}{4}\)
\(=\dfrac{11}{8}\left[\left(\dfrac{5}{11}.\dfrac{-8}{13}-\dfrac{5}{11}.\dfrac{5}{13}\right)-\dfrac{6}{33}\right]-\dfrac{3}{4}\)
\(=\dfrac{11}{8}\left[\dfrac{5}{11}\left(\dfrac{-8}{13}-\dfrac{5}{13}\right)-\dfrac{6}{33}\right]-\dfrac{3}{4}\)
\(=\dfrac{11}{8}\left[\dfrac{5}{11}.\left(-1\right)-\dfrac{6}{33}\right]-\dfrac{3}{4}\)
\(=\dfrac{11}{8}\left[\dfrac{-5}{11}-\dfrac{6}{33}\right]-\dfrac{3}{4}\)
\(=\dfrac{11}{8}\left[\dfrac{-15}{33}-\dfrac{6}{33}\right]-\dfrac{3}{4}\)
\(=\dfrac{11}{8}.\dfrac{-21}{33}-\dfrac{3}{4}\)
\(=\dfrac{-7}{8}-\dfrac{3}{4}\)
\(=\dfrac{-7}{8}-\dfrac{6}{8}\)
\(=\dfrac{-13}{8}\)
b: \(\dfrac{2}{9}\cdot\left[-\dfrac{4}{45}:\left(\dfrac{1}{5}-\dfrac{2}{15}\right)+1\dfrac{2}{3}\right]-\dfrac{-5}{27}\)
\(=\dfrac{2}{9}\cdot\left[-\dfrac{4}{45}:\dfrac{1}{15}+\dfrac{5}{3}\right]+\dfrac{5}{27}\)
\(=\dfrac{2}{9}\left(-\dfrac{4}{3}+\dfrac{5}{3}\right)+\dfrac{5}{27}=\dfrac{2}{27}+\dfrac{5}{27}=\dfrac{7}{27}\)
c: \(\left(\dfrac{4}{5}+\dfrac{-9}{7}\right):\dfrac{2021}{2022}+\left(-\dfrac{5}{7}-\dfrac{-6}{5}\right):\dfrac{2021}{2022}\)
\(=\left(\dfrac{4}{9}-\dfrac{9}{7}-\dfrac{5}{7}+\dfrac{6}{5}\right):\dfrac{2021}{2022}\)
\(=\left(\dfrac{10}{5}-\dfrac{14}{7}\right)\cdot\dfrac{2022}{2021}=0\)
