Question

giúp mình với

Answer 1

d )

\(\left(\dfrac{2}{5}+\dfrac{-5}{-6}\right)+\dfrac{4}{5}\\ =\dfrac{2}{5}+\dfrac{5}{6}+\dfrac{4}{5}\\ =\dfrac{37}{30}+\dfrac{4}{5}\\ =\dfrac{61}{30}\)

e) 

\(\dfrac{-3}{-4}+\left(\dfrac{11}{-15}+\dfrac{-1}{2}\right)\\ =\dfrac{3}{4}+\dfrac{-11}{15}+\dfrac{-1}{2}\\ =\dfrac{1}{60}+\dfrac{-1}{2}\\ =-\dfrac{29}{60}\)

Answer 2

\(d.\left(\dfrac{2}{5}+\dfrac{-5}{-6}\right)+\dfrac{4}{5}\)

\(=\dfrac{2}{5}+\left(-\dfrac{5}{6}\right)+\dfrac{4}{5}\)

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

\(=\dfrac{36}{30}+\left(-\dfrac{25}{30}\right)\)

\(=\dfrac{11}{30}\)

\(e.\dfrac{-3}{-4}+\left(\dfrac{11}{-15}+\dfrac{-1}{2}\right)\)

\(=\dfrac{-3}{-4}+\left(-\dfrac{22}{30}+-\dfrac{15}{30}\right)\)

\(=\dfrac{-3}{-4}+\left(-\dfrac{37}{30}\right)\)

\(=\dfrac{-90}{-120}+\left(-\dfrac{148}{120}\right)\)

\(=\dfrac{90}{120}+\left(-\dfrac{148}{120}\right)\)

\(=-\dfrac{58}{120}=-\dfrac{29}{60}\)