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12 tháng 4 2017

\(\frac{5}{7}\cdot\frac{6}{13}+\frac{5}{7}:\frac{13}{7}-\frac{12}{7}\)\(\frac{30}{91}+\frac{5}{13}-\frac{12}{7}\)=\(\frac{30+35-156}{91}\)=  -1

12 tháng 4 2017

=30/91+5/13-12/7

=5/7-12/7

= -1

3 tháng 3 2020

P/s : nhìn thì khủng thật ! :v

\(B=81.\left[\frac{\left[12-\frac{12}{7}-\frac{12}{289}-\frac{12}{85}\right]}{4-\frac{4}{7}-\frac{4}{289}-\frac{4}{85}}:\frac{5+\frac{5}{13}+\frac{5}{169}+\frac{5}{91}}{6+\frac{6}{13}+\frac{6}{169}+\frac{6}{91}}\right].\frac{158158158}{711711711}\)

\(B=81.\left[\frac{12.\left(1-\frac{1}{7}-\frac{1}{289}-\frac{1}{85}\right)}{4.\left(1-\frac{1}{7}-\frac{1}{289}-\frac{1}{85}\right)}:\frac{5.\left(1+\frac{1}{13}+\frac{1}{169}+\frac{1}{91}\right)}{6.\left(1+\frac{1}{13}+\frac{1}{169}+\frac{1}{91}\right)}\right].\frac{158}{711}\)

\(B=81.\left(\frac{3}{1}:\frac{5}{6}\right).\frac{158}{711}\)

\(B=81.\frac{18}{5}.\frac{158}{711}\)

\(B=\frac{1458}{5}.\frac{158}{711}=\frac{324}{5}\)

Vậy  \(B=\frac{324}{5}\)

4 tháng 5 2018

\(a,\frac{7}{12}\cdot\frac{6}{11}+\frac{7}{12}\cdot\frac{5}{11}+2\frac{7}{12}\)

\(=\frac{7}{12}\cdot\left(\frac{6}{11}+\frac{5}{11}\right)+2\frac{7}{12}\)

\(=\frac{7}{12}+\frac{31}{12}\)

\(=\frac{38}{12}=\frac{19}{6}\)

\(b,\frac{-5}{9}\cdot\frac{-6}{13}+\frac{5}{-9}\cdot\frac{-5}{13}-\frac{5}{9}\)

\(=\frac{-5}{9}\cdot\frac{-6}{13}+\frac{-5}{9}\cdot\frac{-5}{13}+\frac{-5}{9}\cdot1\)

\(=\frac{-5}{9}\cdot\left(\frac{-6}{13}+\frac{-5}{13}+1\right)\)

\(=\frac{-5}{9}\cdot\left(\frac{-11}{13}+1\right)\)

\(=\frac{-5}{9}\cdot\frac{2}{13}\)

\(=\frac{-10}{117}\)

\(c,\)\(0,8\cdot\frac{-15}{14}-\frac{4}{5}\cdot\frac{13}{14}-1\frac{2}{5}\)

\(=\frac{4}{5}\cdot\frac{-15}{14}-\frac{4}{5}\cdot\frac{13}{14}-\frac{7}{5}\)

\(=\frac{4}{5}\cdot\left(\frac{-15}{14}-\frac{13}{14}\right)-\frac{7}{5}\)

\(=\frac{4}{5}\cdot\left(-2\right)-\frac{7}{5}\)

\(=\frac{-8}{5}-\frac{7}{5}\)

\(=-3\)

\(d,\)\(75\%\cdot\frac{6}{7}+5\%\cdot\frac{6}{7}+\frac{7}{10}\cdot1\frac{1}{7}\)

\(=\frac{3}{4}\cdot\frac{6}{7}+\frac{1}{20}\cdot\frac{6}{7}+\frac{7}{10}\cdot\frac{8}{7}\)

\(=\left(\frac{3}{4}+\frac{1}{20}\right)\cdot\frac{6}{7}+\frac{7}{10}\cdot\frac{8}{7}\)

\(=\frac{4}{5}\cdot\frac{6}{7}+\frac{4}{5}\cdot1\)

\(=\frac{4}{5}\cdot\left(\frac{6}{7}+1\right)\)

\(=\frac{4}{5}\cdot\frac{13}{7}\)

\(=\frac{52}{35}\)

4 tháng 5 2018

a)7/12.6/11+7/12.5/11-2.7/12

=7/12(6/11+5/11-2)

=7/12(1-2)

=7/12.(-1)

=-7/12

7 tháng 8 2019

a . 7/12 . 6/11 + 7/12 . 5/11 - 2 7/12

= 7/12 . ( 6/11 + 5/11 ) - 31/12

= 7/12 . 1 - 31/12

= 7/12 - 31/12

= -2

b . -5/9 . -6/13 + 5/-9 . -5/13 - 5/9

= -5/9 . ( -6/13 + -5/13 ) - 5/9

= -5/9 . ( -1 ) -5/9

= 5/9 - 5/9

= 0

21 tháng 3 2017

kb với em với

21 tháng 3 2017

108/91