Violympic toán 7

TH

5/11.(-3/7)+5/11.(-5/7)+(-8/7).6/11

NT
18 tháng 12 2022 lúc 11:45

\(=\dfrac{5}{11}\left(-\dfrac{3}{7}-\dfrac{5}{7}\right)+\dfrac{-8}{7}\cdot\dfrac{6}{11}=\dfrac{-8}{7}\left(\dfrac{5}{11}+\dfrac{6}{11}\right)=-\dfrac{8}{7}\)

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DP
18 tháng 12 2022 lúc 11:46

\(\dfrac{5}{11}.\left(-\dfrac{3}{7}\right)+\dfrac{5}{11}.\left(-\dfrac{5}{7}\right)+\left(-\dfrac{8}{7}\right).\dfrac{6}{11}\)

\(=\dfrac{5}{11}.\left[-\dfrac{3}{7}+\left(-\dfrac{5}{7}\right)\right]+\left(-\dfrac{8}{7}\right).\dfrac{6}{11}\)

\(=\dfrac{5}{11}.\left(-\dfrac{8}{7}\right)+\left(-\dfrac{8}{7}\right).\dfrac{6}{11}=\left(\dfrac{5}{11}+\dfrac{6}{11}\right).\left(-\dfrac{8}{7}\right)\)

\(=1.\left(-\dfrac{8}{7}\right)=-\dfrac{8}{7}\)

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KL
18 tháng 12 2022 lúc 11:47

\(\dfrac{5}{11}.\left(-\dfrac{3}{7}\right)+\dfrac{5}{11}.\left(-\dfrac{5}{7}\right)+\left(-\dfrac{8}{7}\right).\dfrac{6}{11}\)

\(=\dfrac{5}{11}.\left(-\dfrac{3}{7}-\dfrac{5}{7}\right)+\left(-\dfrac{8}{7}\right).\dfrac{6}{11}\)

\(=\dfrac{5}{11}.\left(-\dfrac{8}{7}\right)+\left(-\dfrac{8}{7}\right).\dfrac{6}{11}\)

\(=\left(-\dfrac{8}{7}\right).\left(\dfrac{5}{11}+\dfrac{6}{11}\right)\)

\(=\left(-\dfrac{8}{7}\right).1\)

\(=-\dfrac{8}{7}\)

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BA
18 tháng 12 2022 lúc 11:47

\(\dfrac{5}{11} . \left(-\dfrac{3}{7}\right)+\dfrac{5}{11} . \left(-\dfrac{5}{7}\right)+\left(-\dfrac{8}{7}\right) . \dfrac{6}{11}=\left[\dfrac{5}{11} . \left(-\dfrac{3}{7}+-\dfrac{5}{7}\right)\right]+\left(-\dfrac{8}{7}\right) . \dfrac{6}{11}=\dfrac{5}{11} . \left(-\dfrac{8}{7}\right)+\left(-\dfrac{8}{7}\right) . \dfrac{6}{11}=\left(\dfrac{5}{11}+\dfrac{6}{11}\right) . \left(-\dfrac{8}{7}\right)=1 . \left(-\dfrac{8}{7}\right)=-\dfrac{8}{7}\)

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