Question

Giúp ạ

Answer 1

b) Ta có: \(7\dfrac{1}{6}\cdot\dfrac{-7}{6}+10\dfrac{5}{6}\cdot\dfrac{-7}{6}\)

\(=\dfrac{-7}{6}\left(7+\dfrac{1}{6}+10+\dfrac{5}{6}\right)\)

\(=\dfrac{-7}{6}\cdot18=-21\)

c) Ta có: \(1\dfrac{5}{27}-\dfrac{5}{9}\left(2019\dfrac{2}{5}-2018\dfrac{1}{15}\right)\)

\(=\dfrac{32}{27}-\dfrac{5}{9}\cdot\left(2019+\dfrac{2}{5}-2018-\dfrac{1}{15}\right)\)

\(=\dfrac{32}{27}-\dfrac{5}{9}\cdot\left(1-\dfrac{1}{3}\right)\)

\(=\dfrac{32}{27}-\dfrac{5}{9}\cdot\dfrac{2}{3}\)

\(=\dfrac{32}{27}-\dfrac{10}{27}=\dfrac{22}{27}\)