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3 tháng 10 2019

\(A=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{1}{3}-0,25+0,2}{\frac{7}{6}-0,875+0,7}+\frac{6}{7}\)

\(=\frac{1}{2}.\frac{2}{7}+\frac{6}{7}=1\)

\(A=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{1}{3}-0,25+0,2}{\frac{7}{6}-0,875+0,7}+\frac{6}{7}\)

\(=\frac{1}{2}-\frac{1}{2}-\frac{1}{2}.\frac{5}{6}-\frac{25}{\frac{100}{-\frac{875}{1000}}}+\frac{6}{7}\)

\(=-\frac{1}{2}.\frac{5}{6}-\frac{25}{\frac{100}{\frac{-87,5}{100}}}+\frac{6}{7}\)

\(=-\frac{1}{2}.\frac{5}{6}-\frac{25}{-87,5}+\frac{6}{7}\)

đến đây tự lm == 

16 tháng 4 2020

\(\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{\frac{4}{9}-\frac{4}{7}-\frac{4}{11}}+\frac{\frac{3}{5}-\frac{3}{25}-\frac{3}{125}-\frac{3}{625}}{\frac{4}{5}-\frac{4}{25}-\frac{4}{125}-\frac{4}{625}}\)

\(=\frac{\frac{1}{9}-\frac{1}{7}-\frac{1}{11}}{4\left(\frac{1}{9}-\frac{1}{7}-\frac{1}{11}\right)}+\frac{3\left(\frac{1}{5}-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right)}{4\left(\frac{1}{5}-\frac{1}{25}-\frac{1}{125}-\frac{1}{625}\right)}\)

\(=\frac{1}{4}+\frac{3}{4}=\frac{4}{4}=1\)

29 tháng 3 2022

Hay lắm bn

 

2 tháng 7 2019

a, \(\frac{-5}{9}.\left(\frac{3}{10}-\frac{2}{5}\right)\)

\(=\frac{-5}{9}.\left(\frac{3}{10}-\frac{4}{10}\right)\)

\(=\frac{-5}{9}.\frac{-1}{10}\)

\(=\frac{5}{90}\)

\(=\frac{1}{18}\)

b,\(\frac{2}{3}+\frac{-1}{3}+\frac{7}{15}\)

\(=\frac{10}{15}-\frac{5}{15}+\frac{7}{15}\)

\(=\frac{12}{15}\)

\(=\frac{4}{5}\)

c, \(\frac{3}{8}.3\frac{1}{3}\)

\(=\frac{3}{8}.\frac{10}{3}\)

\(=\frac{10}{8}\)

\(=\frac{5}{4}\)

d, \(\frac{-3}{5}+0,8.\left(-7\frac{1}{2}\right)\)

\(=\frac{-3}{5}+\frac{4}{5}.\frac{-15}{2}\)

\(=\frac{-3}{5}+\frac{-60}{10}\)

\(=\frac{-3}{5}+\frac{-30}{5}\)

\(=\frac{-33}{5}\)

e, \(\frac{2}{5}.8\frac{1}{3}+1\frac{2}{3}.\frac{2}{5}\)

\(=\frac{2}{5}.\left(8\frac{1}{3}+1\frac{2}{3}\right)\)

\(=\frac{2}{5}.10\)

\(=4\)

f, \(\frac{3}{7}.19\frac{1}{3}-\frac{3}{7}.33\frac{1}{3}\)

\(=\frac{3}{7}.\left(19\frac{1}{3}-33\frac{1}{3}\right)\)

\(=\frac{3}{7}.-14\)

\(=-6\)

~Study well~

#KSJ

17 tháng 9 2019

Đáp án = \(\frac{24}{7}\)

Dp là 24 trên 7

Học tốt 

Ace

\(\frac{-1}{3}.\frac{5}{7}-\frac{1}{3}.\frac{-7}{5}\)

\(=\frac{-1}{3}.\frac{5}{7}+\frac{-1}{3}.\frac{-7}{5}\)

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

\(=\frac{-1}{3}.0=0\)