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26 tháng 9 2018

(13/19*19/13)-7/9

=1-7/9

=2/9

26 tháng 9 2018

mọi ng ơi giúp e với

14 tháng 10 2021

\(\frac{13}{19}\times\left(\frac{19}{13}-\frac{7}{9}\right)\\ =\frac{13}{19}\times\frac{19}{13}-\frac{13}{19}\times\frac{7}{9}\)

\(=1-\frac{91}{171}\)

\(=\frac{80}{171}\)

Thấy đúng thì k đúng giúp mik

17 tháng 7 2018

=19/13 + 7/8 + 1/9 + 2/3 + 7/13 + 17/19

=6221/1368

16 tháng 7 2018

\(\frac{19}{13}+\frac{14}{16}+\frac{1}{9}+\frac{4}{6}+\frac{7}{13}+\frac{17}{19}=\frac{6221}{1368}\)

a: \(\left(-\dfrac{5}{6}+\dfrac{2}{5}\right):\dfrac{3}{8}+\left(\dfrac{4}{5}-\dfrac{11}{30}\right):\dfrac{3}{8}\)

\(=\left(-\dfrac{5}{6}+\dfrac{2}{5}\right)\cdot\dfrac{8}{3}+\left(\dfrac{4}{5}-\dfrac{11}{30}\right)\cdot\dfrac{8}{3}\)

\(=\dfrac{8}{3}\left(-\dfrac{5}{6}+\dfrac{2}{5}+\dfrac{4}{5}-\dfrac{11}{30}\right)\)

\(=\dfrac{8}{3}\cdot\dfrac{-25+36-11}{30}\)

=0

b: \(\left(-\dfrac{3}{4}+\dfrac{2}{5}\right):\dfrac{3}{7}+\left(\dfrac{3}{5}+\dfrac{-1}{4}\right):\dfrac{3}{7}\)

\(=\left(-\dfrac{3}{4}+\dfrac{2}{5}\right)\cdot\dfrac{7}{3}+\left(\dfrac{3}{5}-\dfrac{1}{4}\right)\cdot\dfrac{7}{3}\)

\(=\dfrac{7}{3}\left(-\dfrac{3}{4}+\dfrac{2}{5}+\dfrac{3}{5}-\dfrac{1}{4}\right)\)

\(=\dfrac{7}{3}\cdot0=0\)

c: \(\dfrac{-13}{18}\cdot\dfrac{5}{8}+\dfrac{-5}{18}\cdot\dfrac{2}{9}+\dfrac{-13}{18}\cdot\dfrac{3}{8}+\dfrac{-5}{18}\cdot\dfrac{7}{9}\)

\(=\left(-\dfrac{13}{18}\cdot\dfrac{5}{8}+\dfrac{-13}{18}\cdot\dfrac{3}{8}\right)+\left(-\dfrac{5}{18}\cdot\dfrac{2}{9}+\dfrac{-5}{18}\cdot\dfrac{7}{9}\right)\)

\(=-\dfrac{13}{18}\left(\dfrac{5}{8}+\dfrac{3}{8}\right)+\dfrac{-5}{18}\left(\dfrac{2}{9}+\dfrac{7}{9}\right)\)

\(=-\dfrac{13}{18}-\dfrac{5}{18}=-\dfrac{18}{18}=-1\)

d: Sửa đề: \(\dfrac{-11}{19}\cdot\dfrac{4}{9}+\dfrac{-8}{19}\cdot\dfrac{3}{7}+\dfrac{-11}{19}\cdot\dfrac{5}{9}+\dfrac{-8}{19}\cdot\dfrac{4}{7}\)

\(=\left(-\dfrac{11}{19}\cdot\dfrac{4}{9}+\dfrac{-11}{19}\cdot\dfrac{5}{9}\right)+\left(\dfrac{-8}{19}\cdot\dfrac{3}{7}+\dfrac{-8}{19}\cdot\dfrac{4}{7}\right)\)

\(=-\dfrac{11}{19}\left(\dfrac{4}{9}+\dfrac{5}{9}\right)+\dfrac{-8}{19}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)\)

\(=-\dfrac{11}{19}-\dfrac{8}{19}=-\dfrac{19}{19}=-1\)

24 tháng 1

\(a.\left(-\dfrac{5}{6}+\dfrac{2}{5}\right):\dfrac{3}{8}+\left(\dfrac{4}{5}-\dfrac{11}{30}\right):\dfrac{3}{8}\)

\(=\left(-\dfrac{13}{30}\right):\dfrac{3}{8}+\dfrac{13}{30}:\dfrac{3}{8}\)

\(=\left[\left(-\dfrac{13}{30}+\dfrac{13}{30}\right)\right]:\dfrac{3}{8}\)

\(=0:\dfrac{3}{8}=0\)

\(b.\left(-\dfrac{3}{4}+\dfrac{2}{5}\right):\dfrac{3}{7}+\left(\dfrac{3}{5}+-\dfrac{1}{4}\right):\dfrac{3}{7}\)

\(=\left(-\dfrac{7}{20}\right):\dfrac{3}{7}+\dfrac{7}{20}:\dfrac{3}{7}\)

\(=\left[\left(-\dfrac{7}{20}+\dfrac{7}{20}\right)\right]:\dfrac{3}{7}=0:\dfrac{3}{7}=0\)

\(c.-\dfrac{13}{18}.\dfrac{5}{8}+-\dfrac{5}{18}.\dfrac{2}{9}+-\dfrac{13}{18}.\dfrac{3}{8}+-\dfrac{5}{18}.\dfrac{7}{9}\)

\(=\left(\dfrac{5}{8}+\dfrac{3}{8}\right).-\dfrac{13}{18}+\left(\dfrac{2}{9}+\dfrac{7}{9}\right).-\dfrac{5}{18}\)

\(=1.-\dfrac{13}{18}+1.-\dfrac{5}{18}=-\dfrac{13}{18}+-\dfrac{5}{18}=-1\)

\(d.-\dfrac{11}{19}.\dfrac{4}{9}+\dfrac{-8}{19}.\dfrac{3}{7}+-\dfrac{11}{19}.\dfrac{5}{9}+-\dfrac{9}{19}.\dfrac{4}{7}\)

\(=\left(\dfrac{4}{9}+\dfrac{5}{9}\right).-\dfrac{11}{19}+-\dfrac{24}{133}+-\dfrac{36}{133}\)

\(=-\dfrac{11}{19}+-\dfrac{60}{133}=-\dfrac{137}{133}\)

1) Ta có: \(\frac{-4}{7}-\frac{11}{19}+\frac{13}{19}\cdot\frac{-3}{7}+\frac{2}{19}:\frac{-7}{4}\)

\(=\frac{-4}{7}-\frac{11}{19}-\frac{39}{133}-\frac{8}{133}\)

\(=\frac{-76}{133}-\frac{77}{133}-\frac{39}{133}-\frac{8}{133}\)

\(=\frac{-200}{133}\)

2) Ta có: \(\left(\frac{-4}{9}+\frac{3}{5}\right):\frac{1}{\frac{1}{5}}+\left(\frac{1}{5}-\frac{5}{9}\right):\frac{1}{\frac{1}{5}}\)

\(=\left(\frac{-4}{9}+\frac{3}{5}\right)\cdot\frac{1}{5}+\left(\frac{1}{5}-\frac{5}{9}\right)\cdot\frac{1}{5}\)

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

\(=\frac{1}{5}\left(-1+\frac{4}{5}\right)\)

\(=\frac{1}{5}\cdot\frac{-1}{5}=\frac{-1}{25}\)

3) Ta có: \(\frac{4}{5}-\left(-\frac{2}{7}\right)-\frac{7}{10}\)

\(=\frac{4}{5}+\frac{2}{7}-\frac{7}{10}\)

\(=\frac{56}{70}+\frac{20}{70}-\frac{49}{70}\)

\(=\frac{27}{70}\)

4) Ta có: \(\frac{2}{7}-\left(-\frac{13}{15}+\frac{4}{9}\right)-\left(\frac{5}{9}-\frac{2}{15}\right)\)

\(=\frac{2}{7}+\frac{13}{15}-\frac{4}{9}-\frac{5}{9}+\frac{2}{15}\)

\(=\frac{2}{7}+1-1=\frac{2}{7}\)

3 tháng 4 2020

Bạn ơi câu 2 : 1\1\5 là hỗn số mà bạn

16 tháng 12 2023

d: \(-37\cdot\left(-19\right)+37\left(-19\right)\)

\(=-19\left(-37+37\right)\)

\(=-19\cdot0=0\)

e: \(\left(29-9\right)\cdot\left(-9\right)+\left(-13-7\right)\cdot21\)

\(=20\cdot\left(-9\right)+\left(-20\right)\cdot21\)

\(=-20\left(9+21\right)\)

\(=-20\cdot30=-600\)

h: \(12\cdot\left(-47\right)+12\left(-19\right)+\left(-66\right)\cdot88\)

\(=12\left(-47-19\right)+\left(-66\right)\cdot88\)

\(=\left(-66\right)\cdot12+\left(-66\right)\cdot88\)

\(=-66\left(12+88\right)\)

\(=-66\cdot100=-6600\)

25 tháng 7 2015

3 * 7 /9-7 /13 * 5 /19-7 /19 * 8 /13  =    112/57

10 tháng 5 2018

a) \(\frac{58}{19}+\frac{13}{17}+\frac{35}{43}+\frac{119}{19}+\frac{8}{43}\)

\(=\frac{13}{17}+\left(\frac{58}{19}+\frac{119}{19}\right)+\left(\frac{35}{43}+\frac{8}{43}\right)\)

\(=\frac{13}{17}+\frac{204}{19}+1\)

\(=\frac{1808}{133}\)

b) \(\frac{-5}{7}.\frac{2}{11}+\frac{-5}{7}.\frac{9}{11}+\frac{13}{4}\)

\(=\frac{-5}{7}.\left(\frac{2}{11}+\frac{9}{11}\right)+\frac{13}{4}\)

\(=\frac{-5}{7}.1+\frac{13}{4}\)

\(=\frac{71}{28}\)

c) \(\frac{146}{13}-\left(\frac{21}{7}+\frac{68}{13}\right)\)

\(=\left(\frac{164}{13}-\frac{68}{13}\right)+3\)

\(=\frac{135}{13}\)

d) \(\frac{2}{7}.\frac{21}{4}-\frac{2}{7}.\frac{13}{4}\)

\(=\frac{2}{7}.\left(\frac{21}{4}-\frac{13}{4}\right)\)

\(=\frac{2}{7}.\frac{8}{4}\)

\(=\frac{4}{7}\)

P/s: Mk ko chắc nữa!