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18 tháng 8

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18 tháng 8

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a: =6/35x39/54=13/105

b: \(=\dfrac{-5}{7}\left(\dfrac{2}{11}+\dfrac{9}{11}\right)+\dfrac{12}{7}=\dfrac{-5}{7}+\dfrac{12}{7}=1\)

 

28 tháng 2 2022

cảm ơn

 

30 tháng 4 2017

\(\dfrac{-5}{7}.\dfrac{2}{11}-\dfrac{5}{11}.\dfrac{9}{7}-2\dfrac{5}{7}\)

\(=\dfrac{-2}{7}.\dfrac{5}{11}-\dfrac{5}{11}.\dfrac{9}{7}-\dfrac{19}{7}\)

\(=\dfrac{5}{11}.\left(\dfrac{-2}{7}-\dfrac{9}{7}\right)-\dfrac{19}{7}\)

\(=\dfrac{5}{11}.\dfrac{-11}{7}-\dfrac{19}{7}\)

\(=\dfrac{-5}{7}-\dfrac{19}{7}\)

\(=\dfrac{-24}{7}\)

30 tháng 4 2017

\(\dfrac{-5}{7}.\dfrac{2}{11}-\dfrac{5}{11}.\dfrac{9}{7}-2\dfrac{5}{7}\)

\(=\dfrac{-2}{7}.\dfrac{5}{11}-\dfrac{5}{11}.\dfrac{9}{7}-\dfrac{19}{7}\)

\(=\dfrac{5}{7}\left(\dfrac{-2}{7}-\dfrac{9}{7}\right)-\dfrac{19}{7}\)

\(=\dfrac{5}{7}.\dfrac{-11}{7}-\dfrac{19}{7}\)

\(=\dfrac{5.\left(-11\right)}{11.7}-\dfrac{19}{7}\)

\(=\dfrac{-5.11}{11.7}-\dfrac{19}{7}\)

\(=\dfrac{-5}{7}-\dfrac{19}{7}\)

\(=\dfrac{-5-19}{7}\)

\(=\dfrac{\left(-5\right)+\left(-19\right)}{7}\)

\(=\dfrac{-24}{7}\)

12 tháng 5 2017

\(\dfrac{-3}{7}.\dfrac{2}{11}+\left(\dfrac{-3}{7}\right).\dfrac{9}{11}+1.\left(\dfrac{-3}{7}\right)=\left(\dfrac{-3}{7}\right).\left(\dfrac{2}{11}+\dfrac{9}{11}+1\right)=\left(\dfrac{-3}{7}\right).\left(1+1\right)=\dfrac{-3}{7}.2=\dfrac{-6}{7}\)

16 tháng 4 2022

\(\dfrac{5}{7}\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)=\dfrac{5}{7}\times-\dfrac{7}{11}=\dfrac{-5}{11}\)

16 tháng 4 2022

5/7 x ( 5/11 + 2/11 - 14/11) = 5/7 x -7/11 = -5/11

b: \(27D=3^{14}+3^{17}+...+3^{2024}\)

\(\Leftrightarrow26D=3^{2024}-3^{11}\)

hay \(D=\dfrac{3^{2024}-3^{11}}{26}\)

c: \(25E=-5^4-5^6-...-5^{1002}\)

\(\Leftrightarrow24E=-5^{1002}+5^2\)

hay \(E=\dfrac{-5^{1002}+5^2}{24}\)

16 tháng 1 2022

sai nha

 

12 tháng 4 2017

\(\dfrac{5}{7}.\dfrac{5}{11}+\dfrac{5}{7}.\dfrac{8}{11}-\dfrac{5}{7}.\dfrac{2}{11}\)

= \(\dfrac{5}{7}\left(\dfrac{5}{11}+\dfrac{8}{11}-\dfrac{2}{11}\right)\)

= \(\dfrac{5}{7}.\dfrac{5+8-2}{11}\)

= \(\dfrac{5}{7}.\dfrac{11}{11}\)

= \(\dfrac{5}{7}.1=\dfrac{5}{7}\)

25 tháng 8 2015

tính theo công thức bạn nhé

22 tháng 4 2018

\(\frac{22}{25}\times\frac{5}{11}-\frac{33}{25}:\frac{11}{5}+\frac{58}{11}\)

\(=\frac{22}{25}\times\frac{5}{11}-\frac{33}{25}\times\frac{5}{11}+\frac{58}{11}\)

\(=\frac{5}{11}\times\left(\frac{22}{25}+\frac{33}{25}\right)+\frac{58}{11}\)

\(=\frac{5}{11}\times\frac{11}{5}+\frac{58}{11}\)

\(=1+\frac{58}{11}\)

\(=\frac{11}{11}+\frac{58}{11}\)

\(=\frac{69}{11}\)

\(8\frac{3}{11}-\left(3\frac{5}{7}-7\frac{8}{11}\right)\)

\(=\frac{91}{11}-\left(\frac{26}{7}-\frac{85}{11}\right)\)

\(=\frac{91}{11}-\frac{26}{7}+\frac{85}{11}\)

\(=\frac{91}{11}+\frac{85}{11}-\frac{26}{7}\)

\(=16-\frac{26}{7}\)

\(=\frac{86}{7}\)

\(\frac{5}{6}x+325\%=\frac{3}{2}x-30,75\)

\(=>\frac{5}{6}x+3,25=\frac{3}{2}x-30,75\)

\(=>\frac{5}{6}x-\frac{3}{2}x=-30,75-3,25\)

\(=>\frac{-2}{3}x=-34\)

\(=>x=-34:\left(-\frac{2}{3}\right)\)

\(=>x=-34.\left(\frac{3}{-2}\right)\)

\(=>x=51\)