Bài 5: Thực hiện phép tính ( Tính hợp lí nếu có thể ):e) \(\dfrac{-3}{8}\) . \(\dfrac{5}{12}\) + \(\dfrac{7}{12}\) . \(\dfrac{-3}{8}\) + ( -2022 )0f) \(\dfrac{2}{9}\) . \(\dfrac{-4}{7}\) . \(\dfrac{-9}{2}\)g) \(\dfrac{15}{8}\) :...
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Bài 5: Thực hiện phép tính ( Tính hợp lí nếu có thể ):
e) \(\dfrac{-3}{8}\) . \(\dfrac{5}{12}\) + \(\dfrac{7}{12}\) . \(\dfrac{-3}{8}\) + ( -2022 )0
f) \(\dfrac{2}{9}\) . \(\dfrac{-4}{7}\) . \(\dfrac{-9}{2}\)
g) \(\dfrac{15}{8}\) : ( \(\dfrac{25}{8}\) + \(\dfrac{-11}{2}\))
h) \(\dfrac{-5}{6}\) . \(\dfrac{4}{19}\) + \(\dfrac{-7}{12}\) . \(\dfrac{4}{19}\) - \(\dfrac{40}{57}\)
e: \(\dfrac{-3}{8}\cdot\dfrac{5}{12}+\dfrac{7}{12}\cdot\dfrac{-3}{8}+\left(-2022\right)^0\)
\(=\dfrac{-3}{8}\left(\dfrac{5}{12}+\dfrac{7}{12}\right)+1\)
\(=-\dfrac{3}{8}+1=\dfrac{5}{8}\)
f: \(\dfrac{2}{9}\cdot\dfrac{-4}{7}\cdot\dfrac{-9}{2}=\dfrac{2}{2}\cdot\dfrac{9}{9}\cdot\dfrac{4}{7}=\dfrac{4}{7}\)
g: \(\dfrac{15}{8}:\left(\dfrac{25}{8}+\dfrac{-11}{2}\right)\)
\(=\dfrac{15}{8}:\dfrac{25-44}{8}=\dfrac{15}{8}\cdot\dfrac{8}{-19}=-\dfrac{15}{19}\)
h: \(\dfrac{-5}{6}\cdot\dfrac{4}{19}+\dfrac{-7}{12}\cdot\dfrac{4}{19}-\dfrac{40}{57}\)
\(=\dfrac{4}{19}\left(-\dfrac{5}{6}-\dfrac{7}{12}-\dfrac{10}{3}\right)\)
\(=\dfrac{4}{19}\cdot\dfrac{-10-7-40}{12}=\dfrac{4}{12}\cdot\dfrac{-57}{19}=\dfrac{-3}{3}=-1\)