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\(\left(2+\frac{5}{6}\right)\div1\frac{1}{5}+\frac{-7}{12}\)
\(=\left(\frac{12}{6}+\frac{5}{6}\right)\div\frac{6}{5}-\frac{7}{12}\)
\(=\frac{17}{6}\div\frac{6}{5}-\frac{7}{12}\)
\(=\frac{17}{6}\times\frac{5}{6}-\frac{7}{12}\)
\(=\frac{85}{12}-\frac{7}{12}\)
\(=\frac{78}{12}=\frac{13}{2}\)
\(\left(15-6\frac{13}{18}\right)\div11\frac{1}{7}-2\frac{1}{8}\div1\frac{11}{40}\)
\(=9\frac{13}{18}\div\frac{78}{7}-\frac{17}{8}\div\frac{51}{40}\)
\(=\frac{175}{18}\div\frac{78}{7}-\frac{17}{8}\times\frac{40}{51}\)
\(=\frac{175}{18}\times\frac{7}{78}-\frac{5}{3}\)
\(=\frac{1225}{1404}-\frac{5}{3}\)
\(=\frac{1225}{1404}-\frac{2340}{1404}\)
\(=\frac{-1115}{1404}\)
a) \(\frac{-5}{8}\cdot\left(\frac{4}{9}+\frac{-7}{12}\right)\)
\(=\frac{-5}{8}\cdot\frac{-5}{36}\)
\(=\frac{25}{288}\)
b) \(\left(-3,2\right)\cdot\frac{-15}{64}+\left(0,8-2\frac{4}{5}\right):3\frac{1}{2}\)
\(=\frac{3}{4}+\left(-2\right):\frac{7}{2}\)
\(=\frac{3}{4}+\frac{-4}{7}\)
\(=\frac{5}{28}\)
=))
Bài 2
a, \(\dfrac{4}{5}+\dfrac{2}{7}-\dfrac{7}{10}=\) \(\dfrac{27}{70}\)
Bài 1:
b) \(\frac{-3}{4}\) và \(-0,8\)
Ta có: \(\frac{-3}{4}=\frac{-15}{20}\) ; \(-0,8=\frac{-8}{10}=\frac{-16}{20}\)
So sánh: \(\frac{-15}{20}>\frac{-16}{20}\)
=> \(\frac{-3}{4}>-0,8\)
Bài 2:
a) \(\frac{4}{5}+\frac{2}{7}-\frac{7}{10}\)
= \(\frac{56}{70}+\frac{20}{70}-\frac{49}{70}\)
= \(\frac{27}{70}\)
Câu b tương tự nhưng MSC là 12 nha, đúng thì k cho mik.
a: \(=\left(-\dfrac{25}{140}+\dfrac{245}{140}+\dfrac{32}{140}\right)\cdot\dfrac{-69}{20}\)
\(=\dfrac{252}{140}\cdot\dfrac{-69}{20}\)
\(=\dfrac{9}{5}\cdot\dfrac{-69}{20}=\dfrac{-621}{100}\)
b: \(=\left(6-2-\dfrac{4}{5}\right)\cdot\dfrac{25}{8}-\dfrac{8}{5}\cdot4\)
\(=\dfrac{16}{5}\cdot\dfrac{25}{8}-\dfrac{32}{5}=\dfrac{18}{5}\)
c: \(=\left(\dfrac{2}{24}+\dfrac{18}{24}+\dfrac{14}{24}\right):\dfrac{-17}{8}\)
\(=\dfrac{34}{24}\cdot\dfrac{-8}{17}=\dfrac{-1}{3}\cdot2=-\dfrac{2}{3}\)
a: \(=\left(\dfrac{37}{7}\cdot\dfrac{8}{11}+\dfrac{2}{11}\cdot\dfrac{37}{7}\right):\dfrac{37}{11}-\dfrac{10}{7}\)
\(=\dfrac{37}{7}\cdot\dfrac{11}{37}\cdot\dfrac{10}{11}-\dfrac{10}{7}\)
\(=\dfrac{10}{7}-\dfrac{10}{7}=0\)
b: \(=\left[\dfrac{4}{5}:1\right]:\dfrac{16-1}{25}=\dfrac{4}{5}\cdot\dfrac{25}{15}=\dfrac{4}{5}\cdot\dfrac{5}{3}=\dfrac{4}{3}\)
c: \(=6.97+\dfrac{-7}{12}-\dfrac{11}{24}-5.57\)
\(=1.4-\dfrac{25}{24}=\dfrac{43}{120}\)
Lời giải:
\(1\frac{1}{3}:0,8=\frac{2}{3}:(0,1x)\)
\(\frac{4}{3}:\frac{8}{10}=\frac{2}{3}:\frac{x}{10}\)
\(\frac{5}{3}=\frac{2}{3}:\frac{x}{10}\)
\(\frac{x}{10}=\frac{2}{3}:\frac{5}{3}=\frac{2}{5}\)
\(x=\frac{2}{5}.10=4\)
\(1\frac{1}{3}:0,8=\frac{2}{3}:\left(0,1x\right)\)
\(\frac{4}{3}:\frac{8}{10}=\frac{2}{3}.\frac{10}{x}\)
\(\frac{4}{3}.\frac{5}{4}=\frac{20}{3x}\)
\(\frac{5}{3}=\frac{20}{3x}\)
\(\frac{1}{x}=\frac{5}{3}.\frac{3}{20}\)
\(\frac{1}{x}=\frac{1}{4}\)
\(x=4\)