Question

[Dan Nguyen Huu]

Help túi với mn

Answer 1

[Nguyễn Lê Phước Thịnh]

a) Ta có: \(\dfrac{-1}{24}-\left[\dfrac{1}{4}-\left(\dfrac{1}{2}-\dfrac{7}{8}\right)\right]\)

\(=\dfrac{-1}{24}-\left(\dfrac{1}{4}-\dfrac{1}{2}+\dfrac{7}{8}\right)\)

\(=\dfrac{-1}{24}-\dfrac{1}{4}+\dfrac{1}{2}-\dfrac{7}{8}\)

\(=\dfrac{-1}{24}-\dfrac{6}{24}+\dfrac{12}{24}-\dfrac{21}{24}\)

\(=\dfrac{-16}{24}=\dfrac{-2}{3}\)

b) Ta có: \(\left(\dfrac{5}{7}-\dfrac{7}{5}\right)-\left[\dfrac{1}{2}-\left(\dfrac{-2}{7}-\dfrac{1}{10}\right)\right]\)

\(=\dfrac{25-49}{35}-\left(\dfrac{1}{2}+\dfrac{2}{7}+\dfrac{1}{10}\right)\)

\(=\dfrac{-24}{35}-\dfrac{1}{2}-\dfrac{2}{7}-\dfrac{1}{10}\)

\(=\dfrac{-48}{70}-\dfrac{35}{70}-\dfrac{20}{70}-\dfrac{7}{70}\)

\(=\dfrac{-110}{70}=\dfrac{-11}{7}\)