CT
H24
2 tháng 2 2022 lúc 19:04

\(e,\dfrac{1}{5}.10-\dfrac{1}{3}.\left(-2\right)\\ =2-\dfrac{-2}{3}=\dfrac{8}{3}\\ f,\dfrac{-7}{8}.\dfrac{16}{21}-\dfrac{5}{3}.\left(-2\right)\) 

\(=\dfrac{-2}{3}-\dfrac{10}{3}=\left(-4\right)\)

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H24
2 tháng 2 2022 lúc 19:08

-Bài cuối cùng mình làm :)

e) \(\dfrac{1}{5}:\dfrac{1}{10}-\dfrac{1}{3}\left(\dfrac{6}{5}-\dfrac{9}{4}\right)\)

=\(\dfrac{1}{5}.10-\dfrac{1}{3}.\dfrac{6}{5}+\dfrac{1}{3}.\dfrac{9}{4}\)

=\(2-\dfrac{2}{5}+\dfrac{3}{4}\)=\(\dfrac{40}{20}-\dfrac{8}{20}+\dfrac{15}{20}\)=\(\dfrac{47}{20}\).

f) \(\dfrac{7}{8}:\dfrac{21}{16}-\dfrac{5}{3}\left(\dfrac{1}{5}-\dfrac{7}{10}\right)\)

=\(\dfrac{7}{8}.\dfrac{16}{21}-\dfrac{5}{3}.\dfrac{1}{5}+\dfrac{5}{3}.\dfrac{7}{10}\)=\(\dfrac{2}{3}-\dfrac{1}{3}+\dfrac{7}{6}\)

=\(\dfrac{4}{6}-\dfrac{2}{6}+\dfrac{7}{6}\)=\(\dfrac{9}{6}\)=\(\dfrac{3}{2}\)

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SK
2 tháng 2 2022 lúc 19:09

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