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17 tháng 5 2022
a: \(=\dfrac{-3}{7}+\dfrac{15}{26}-\dfrac{2}{13}+\dfrac{3}{7}=\dfrac{15}{26}-\dfrac{4}{26}=\dfrac{11}{26}\)
b: \(=\dfrac{6}{7}+\dfrac{2}{9}-\dfrac{10}{7}-5=\dfrac{-4}{7}-5+\dfrac{2}{9}=-\dfrac{337}{63}\)
c: \(=-\dfrac{11}{23}\left(\dfrac{6}{7}+\dfrac{8}{7}\right)-\dfrac{1}{23}=\dfrac{-22}{23}-\dfrac{1}{23}=-1\)
1 tháng 4 2015
Bài 1:
a) \(-\frac{3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)\)
\(=-\frac{3}{7}+\frac{15}{26}-\frac{4}{26}+\frac{3}{7}\)
\(=\left(-\frac{3}{7}+\frac{3}{7}\right)+\left(\frac{15}{26}-\frac{4}{26}\right)\)
\(=0+\frac{11}{26}\)
\(=\frac{11}{26}\)
b)\(2\frac{3}{7}+\frac{2}{9}-1\frac{3}{7}\)
\(=\frac{17}{7}+\frac{2}{9}-\frac{10}{7}\)
\(=\left(\frac{17}{7}-\frac{10}{7}\right)+\frac{2}{9}\)
\(=1+\frac{2}{9}\)
\(=1\frac{2}{9}=\frac{11}{9}\)
c)\(\left(\frac{377}{-231}-\frac{124}{89}+\frac{34}{791}\right).\left(\frac{1}{6}-\frac{1}{8}-\frac{1}{24}\right)\)
\(=\left(\frac{377}{-231}-\frac{124}{89}+\frac{34}{791}\right).\left(\frac{4}{24}-\frac{3}{24}-\frac{1}{24}\right)\)
\(=\left(\frac{377}{-231}-\frac{124}{89}+\frac{34}{791}\right).0\)
\(=0\)
31 tháng 5 2016
B1:
a,\(\frac{-3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)\)
\(\Rightarrow\frac{-3}{7}+\frac{15}{26}-\frac{2}{13}+\frac{3}{7}\)
\(\Rightarrow\left(\frac{-3}{7}+\frac{3}{7}\right)+\frac{15}{26}-\frac{4}{26}\)
\(\Rightarrow\frac{15}{26}-\frac{4}{26}\)
=\(\frac{11}{26}\)
1 tháng 6 2016
b,\(\frac{23}{7}+\frac{2}{9}-\frac{13}{7}\)
\(=\frac{23}{7}-\frac{13}{7}+\frac{2}{9}\)
\(=\frac{10}{7}+\frac{2}{9}\)
\(=\frac{104}{63}\)
15 tháng 6 2018
1)
\(2.\frac{3}{7}+\left(\frac{2}{9}-1\frac{3}{7}\right)-\frac{5}{3}:\frac{1}{9}\)
\(=\frac{6}{7}+\frac{2}{9}-\frac{10}{7}-\frac{5}{3}.9\)
\(=\left(\frac{6}{7}-\frac{10}{7}\right)+\frac{2}{9}-15\)
\(=\frac{-4}{7}+\frac{2}{9}-\frac{15}{1}\)
\(=\frac{-36}{63}+\frac{14}{63}-\frac{945}{63}\)
\(=\frac{-967}{63}\)
2)
\(-\frac{11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}\)
\(=\frac{-11}{23}\left(\frac{6}{7}+\frac{8}{7}\right)-\frac{1}{23}\)
\(=\frac{-11}{23}.2-\frac{1}{23}\)
\(=\frac{-22}{23}-\frac{1}{23}\)
\(=\frac{-23}{23}\)
\(=-1\)
3)
\(\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right).\left(\frac{1}{6}-\frac{1}{8}-\frac{1}{24}\right)\)
\(=\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right).\left(\frac{4}{24}-\frac{3}{24}-\frac{1}{24}\right)\)
\(=\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right).\frac{0}{24}\)
\(=\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right).0\)
\(=0\)
VD
2
17 tháng 2 2022
\(=\left(\dfrac{377}{-231}-\dfrac{123}{89}+\dfrac{34}{791}\right)\cdot\left(\dfrac{4}{24}-\dfrac{3}{24}-\dfrac{1}{24}\right)=0\)
1 tháng 5 2019
a) \(\frac{-3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)=\frac{-3}{7}+\frac{15}{26}-\frac{2}{13}+\frac{3}{7}=\left(\frac{-3}{7}+\frac{3}{7}\right)+\left(\frac{15}{26}-\frac{2}{13}\right)\)
\(=\frac{15-4}{26}=\frac{11}{26}\)
1 tháng 5 2019
c) \(\frac{-11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}=\frac{-11}{23}.\left(\frac{6}{7}+\frac{8}{7}\right)-\frac{1}{23}\)
\(=\frac{-11}{23}.2-\frac{1}{23}=\frac{-22-1}{23}=\frac{-23}{23}=-1\)
29 tháng 6 2022
a: \(=-9+\left\{-52:9\right\}=-9+\dfrac{-52}{9}=-\dfrac{133}{9}\)
b: \(=\dfrac{17}{7}+\left(\dfrac{-76}{63}\right):15\)
\(=\dfrac{17}{7}-\dfrac{76}{63}\cdot\dfrac{1}{15}=\dfrac{317}{135}\)
e: \(=\dfrac{-5}{13}\cdot\dfrac{7}{3}-\dfrac{2}{7}\cdot\dfrac{8}{13}+\dfrac{5}{13}\cdot\dfrac{1}{7}\)
\(=\dfrac{5}{13}\left(-\dfrac{7}{3}+\dfrac{1}{7}\right)-\dfrac{2}{7}\cdot\dfrac{8}{13}\)
\(=\dfrac{5}{13}\cdot\dfrac{-46}{21}-\dfrac{16}{91}=\dfrac{-278}{273}\)
\(\left(3x-2^4\right)\cdot5=370\)
\(3x-16=74\)
\(3x=90\)
\(x=30\)
\(\left(3x-2^4\right).5=370\)
\(3x-16=74\)
\(3x=90\)
\(\Rightarrow x=30\)