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21 tháng 3 2017

C=\(\frac{132}{67}\)

21 tháng 3 2017

giải chi tiết giùm cái 

19 tháng 3 2017

\(\dfrac{4}{1.3}+\dfrac{12}{3.9}+\dfrac{16}{9.17}+\dfrac{30}{17.32}+\dfrac{26}{32.45}+\dfrac{10}{45.50}+\dfrac{34}{50.67} =2.\left(\dfrac{2}{1.3}+\dfrac{6}{3.9}+\dfrac{8}{9.17}+\dfrac{15}{17.32}+\dfrac{13}{32.45}+\dfrac{5}{45.50}+\dfrac{17}{50.67}\right)=2\left(\dfrac{1}{1}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{9}+\dfrac{1}{9}-\dfrac{1}{17}+...\dfrac{1}{45}-\dfrac{1}{50}+\dfrac{1}{50}-\dfrac{1}{67}\right)=2\left(1-\dfrac{1}{67}\right)=2.\dfrac{66}{67}=\dfrac{132}{67}\)

16 tháng 6 2017

a) \(\frac{13}{26}-\frac{1}{3}-\frac{1}{2}+\frac{7}{21}\)
\(=\frac{1}{2}-\frac{1}{3}-\frac{1}{2}+\frac{1}{3}\)
\(=\frac{1}{2}-\frac{1}{2}+\frac{1}{3}-\frac{1}{3}\)
\(=0+0\)
\(=0\)

b) \(\left(\frac{-5}{12}+\frac{6}{11}\right)+\left(\frac{7}{17}+\frac{5}{17}+\frac{5}{12}\right)\)
\(=\frac{-5}{12}+\frac{6}{11}+\frac{7}{17}+\frac{5}{17}+\frac{5}{12}\)
\(=\left(\frac{-5}{12}+\frac{5}{12}\right)+\left(\frac{7}{17}+\frac{5}{17}\right)+\frac{6}{11}\)
\(=0+\frac{12}{17}+\frac{6}{11}\)
\(=\frac{132}{187}+\frac{102}{187}\)
\(=\frac{234}{187}\)

c) \(\left(\frac{13}{5}+\frac{7}{16}\right)-\left(\frac{11}{16}-\frac{12}{10}\right)\)
\(=\left(\frac{13}{5}+\frac{7}{16}\right)-\left(\frac{11}{16}-\frac{6}{5}\right)\)
\(=\frac{13}{5}+\frac{7}{16}-\frac{11}{16}+\frac{6}{5}\)
\(=\left(\frac{13}{5}+\frac{6}{5}\right)+\left(\frac{7}{16}-\frac{11}{16}\right)\)
\(=\frac{19}{5}+\left(\frac{-4}{16}\right)\)
\(=\frac{19}{5}-\frac{1}{4}\)
\(=\frac{76}{20}-\frac{5}{20}\)
\(=\frac{71}{20}\)

d) \(-\left(\frac{3}{10}-\frac{6}{11}\right)-\left(\frac{21}{30}-\frac{5}{11}\right)\)
\(=-\left(\frac{3}{10}-\frac{6}{11}\right)-\left(\frac{7}{10}-\frac{5}{11}\right)\)
\(=-\frac{3}{10}+\frac{6}{11}-\frac{7}{10}+\frac{5}{11}\)
\(= \left(-\frac{3}{10}-\frac{7}{10}\right)+\left(\frac{6}{11}+\frac{5}{11}\right)\)
\(=\frac{-10}{10}+\frac{11}{11}\)
\(=-1+1\)
\(=0\)

23 tháng 2 2021

mik ko hieu lam

30 tháng 4 2019

1/ Tính:

\(\frac{3}{2}-\frac{5}{6}+\frac{7}{12}-\frac{9}{20}+\frac{11}{30}-\frac{13}{42}+\frac{15}{56}-\frac{17}{72}+\frac{19}{90}\) 

\(=\frac{3}{1.2}-\frac{5}{2.3}+\frac{7}{3.4}-\frac{9}{4.5}+\frac{11}{5.6}-\frac{13}{6.7}+\frac{15}{7.8}-\frac{17}{8.9}+\frac{19}{9.10}\) 

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{9}-\frac{1}{10}\) 

\(=1-\frac{1}{10}\) 

\(=\frac{9}{10}\)

24 tháng 10 2019

A=\(\frac{16^3.3^{10}+120.6^9}{4^6.3^{12}+6^{11}}=\frac{\left(2^4\right)^3.3^{10}+2^3.3.5.2^9.3^9}{\left(2^2\right)^6.3^{12}+2^{11}.3^{11}}\)

\(=\frac{2^{12}.3^{10}+2^{12}.3^{10}.5}{2^{12}.3^{12}+2^{11}.3^{11}}\)

\(=\frac{2^{12}.3^{10}.\left(1+5\right)}{2^{11}.3^{11}.\left(2.3+1\right)}\)

\(=\frac{2.6}{3.7}\)\(=\frac{4}{7}\)

13 tháng 8 2015

Jang Ha Na làm sai nhé!!!

\(A=\frac{\left(140\frac{7}{30}-138\frac{5}{12}\right):18\frac{1}{6}}{0,002}\)

\(A=\frac{\left(\frac{4207}{30}-\frac{1661}{12}\right):\frac{109}{6}}{\frac{1}{500}}\)

\(A=\frac{\left(\frac{4207}{30}-\frac{1661}{12}\right)\times\frac{6}{109}}{\frac{1}{500}}\)

\(A=\left(\frac{4207}{30}-\frac{1661}{12}\right)\times\frac{6}{109}\times500\)

\(A=\frac{109}{60}\times\frac{6}{109}\times500\)

\(A=\frac{1}{10}\times500\)

\(A=50\)

3 tháng 7 2018

\(B=\frac{155-\frac{10}{7}-\frac{5}{11}+\frac{5}{23}}{403-\frac{26}{7}-\frac{13}{11}+\frac{13}{23}}\)

\(B=\frac{5\left(31-\frac{2}{7}-\frac{1}{11}+\frac{1}{23}\right)}{13\left(31-\frac{2}{7}-\frac{1}{11}+\frac{1}{23}\right)}\)

\(B=\frac{5}{13}\)