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9 tháng 7 2019

\(D=\frac{5}{8}:\frac{9}{-2}+\frac{5}{8}:\frac{-9}{7}+1\frac{5}{8}\)

\(=\frac{5}{8}.\frac{-2}{9}+\frac{5}{8}.\frac{-7}{9}+\frac{13}{8}\)

\(=\frac{5}{8}.\left(\frac{-2}{9}+\frac{-7}{9}\right)+\frac{13}{8}\)

\(=\frac{-5}{8}+\frac{13}{8}\)

\(=1\)

9 tháng 7 2019

D = \(\frac{5}{8}:\frac{9}{-2}+\frac{5}{8}:\frac{-9}{7}+1\frac{5}{8}\)

    = \(\frac{5}{8}.\frac{-2}{9}+\frac{5}{8}.\frac{-7}{9}+1+\frac{5}{8}\)

    = \(\frac{5}{8}.\left(\frac{-2}{9}+\frac{-7}{9}\right)+1+\frac{5}{8}\)

     = \(-\frac{5}{8}+1+\frac{5}{8}\)

     = \(-\frac{5}{8}+\frac{5}{8}+1\)

     = \(1\)

25 tháng 2 2017

giup minh voi

25 tháng 2 2017

\(\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}:\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)

\(=\frac{2\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}{7\left(\frac{1}{5}-\frac{1}{9}+\frac{1}{11}\right)}:\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{2}\left(\frac{1}{3}-\frac{1}{4}+\frac{1}{5}\right)}\)

\(=\frac{2}{7}:\frac{1}{\frac{7}{2}}=\frac{2}{7}:\frac{2}{7}=1\)

26 tháng 7 2016

c)\(=\frac{-3.5}{7.3^2}+\frac{2^2\cdot-3}{3^2\cdot7}+\frac{17}{7}=\frac{-5}{21}-\frac{4}{21}+2\frac{3}{7}=\frac{-9}{21}+2\frac{3}{7}=\frac{-3}{7}+2\frac{3}{7}=2\)

d)\(=8\frac{2}{7}-3\frac{4}{9}-4\frac{2}{7}=4-3\frac{4}{9}=\frac{36-31}{9}=\frac{5}{9}\)

6 tháng 6 2016

e) \(E=0,7.2\frac{2}{3}.20.0,375.\frac{5}{28}\)

        \(=\left(0,7.20\right)\left(2\frac{2}{3}.0,375\right)\frac{5}{28}\)

        \(=14.1.\frac{5}{28}\)

        \(=14.\frac{5}{28}\)

        \(=\frac{5}{2}\)

f) \(F=\left(9,75.21\frac{3}{7}+\frac{39}{4}.18\frac{4}{7}\right)\frac{15}{78}\)

       \(=\left(\frac{39}{4}.21\frac{3}{7}+\frac{39}{4}.18\frac{4}{7}\right)\frac{15}{78}\)

       \(=\frac{39}{4}\left(21\frac{3}{7}+18\frac{4}{7}\right)\frac{15}{78}\)

       \(=\frac{39}{4}.40.\frac{15}{78}\)

       \(=390.\frac{15}{78}\)

       \(=78\)

Chúc bạn học tốt môn Toán!!!

6 tháng 6 2016

Mình ko ghi đề đâu

\(A=49\frac{8}{23}-5\frac{7}{32}-14\frac{8}{23}=\left(49\frac{8}{23}-14\frac{8}{23}\right)-5\frac{7}{32}=35-5\frac{7}{32}=29\frac{25}{32}\)

\(B=71\frac{38}{45}-43\frac{8}{45}+1\frac{17}{57}=\left(71\frac{38}{45}-43\frac{8}{45}\right)+1\frac{17}{57}=28\frac{2}{3}+1\frac{17}{57}=29\frac{55}{57}\)

\(C=-\frac{3}{7}.\left(\frac{5}{9}+\frac{4}{9}\right)+2\frac{3}{7}=-\frac{3}{7}.1+2\frac{3}{7}=-\frac{3}{7}+2\frac{3}{7}=2\)

7 tháng 8 2019

a . ( -1/3 ) . 9/11 + ( -8/9 ) . 27

= 9/3 . ( -1/11 ) + 27/9 . ( -8 )

= 3 . ( -1/11 ) + 3 . ( -8 )

= 3 . ( -1/11 + ( -8 ) )

= 3 . ( -89/11 )

= -267/11

b . ( 1/2 - 13/14 ) : 5/7 - ( - - 2/21 + 1/7 ) : 5/7

= -3/7 : 5/7 - 5/21 : 5/7

= ( -3/7 - 5/21 ) : 5/7

= -2/3 : 5/7

= -14/15

2 tháng 8 2015

\(=\frac{5\left(\frac{1}{3}+\frac{1}{8}-\frac{1}{7}\right)}{-4\left(\frac{1}{3}+\frac{1}{8}-\frac{1}{7}\right)}:\frac{2\left(\frac{1}{3}-\frac{1}{12}+\frac{3}{7}\right)}{ }\)

MÃu thứ hai sao ý 

2 tháng 8 2015

 lưu tuấn ngiaz  nơi đúng 

25 tháng 7 2016

a)\(\frac{6}{7}+\frac{5}{7}:5-\frac{8}{9}=\frac{6}{7}+\frac{1}{7}-\frac{8}{9}=1-\frac{8}{9}=\frac{1}{9}\)

b)\(\frac{-5}{7}.\frac{2}{11}+\frac{5}{7}.\frac{9}{11}=\frac{5}{7}.\frac{2}{11}-\frac{5}{7}.\frac{9}{11}=\frac{5}{7}.\left(\frac{2}{11}-\frac{9}{11}\right)=\frac{5}{7}.\frac{-7}{11}=\frac{-5}{11}\)

c)\(\frac{5}{9}.\frac{7}{13}+\frac{5}{9}.\frac{9}{13}-\frac{5}{9}.\frac{3}{13}=\frac{5}{9}.\left(\frac{7}{13}+\frac{9}{13}-\frac{3}{13}\right)=\frac{5}{9}.1=\frac{5}{9}\)

25 tháng 7 2016

a) \(\frac{6}{7}+\frac{5}{7}:5-\frac{8}{9}\)
\(\Rightarrow\frac{6}{7}+\frac{1}{7}-\frac{8}{9}\)
\(\Rightarrow1-\frac{8}{9}=\frac{1}{9}\)
b) \(\frac{-5}{7}.\frac{2}{11}+\frac{5}{7}.\frac{9}{11}\)
\(\Rightarrow\frac{5}{7}.\frac{-2}{11}+\frac{5}{7}.\frac{9}{11}\)
\(\Rightarrow\frac{5}{7}.\left(\frac{-2}{11}+\frac{9}{11}\right)\)
\(\Rightarrow\frac{5}{7}.\frac{7}{11}=\frac{5}{11}\)
c) \(\frac{5}{9}.\left(\frac{7}{13}+\frac{9}{13}-\frac{3}{13}\right)=\frac{5}{9}.1=\frac{5}{9}\)