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a)\(\frac{5}{12}:\frac{2}{5}+\frac{7}{12}:\frac{2}{5}-\frac{1}{3}:\frac{2}{5}=\left(\frac{5}{12}+\frac{7}{12}-\frac{1}{3}\right):\frac{2}{5}=\frac{2}{3}:\frac{2}{5}=\frac{5}{3}.\)

b) \(\left(6,7+2,3+5,8\right):1,2=14,8:1,2=\frac{148}{10}:\frac{12}{10}=\frac{148}{12}=\frac{74}{6}=\frac{37}{3}\)

hk tốt!

10 tháng 5 2019

=25/24 + 35/24 - 5/6

=60/24 - 5/6

=15/6 - 5/6

=15-5/6

=10/6

=5/3

mình chỉ biết í a thôi

HQ
Hà Quang Minh
Giáo viên
7 tháng 10 2023

a) \(\frac{{ - 3}}{7}.\frac{2}{5} + \frac{2}{5}.\left( { - \frac{5}{{14}}} \right) - \frac{{18}}{{35}}\)

\(\begin{array}{l} = \frac{2}{5}.\left( {\frac{{ - 3}}{7} + \frac{{ - 5}}{{14}}} \right) - \frac{{18}}{{35}}\\ = \frac{2}{5}.\left( {\frac{{ - 6}}{{14}} + \frac{{ - 5}}{{14}}} \right) - \frac{{18}}{{35}}\\ = \frac{2}{5}.\frac{{ - 11}}{{14}} - \frac{{18}}{{35}} = \frac{{ - 11}}{{35}} - \frac{{18}}{{35}} =  \frac{{ -29}}{{35}}\end{array}\)

b) \(\left( {\frac{2}{3} - \frac{5}{{11}} + \frac{1}{4}} \right):\left( {1 + \frac{5}{{12}} - \frac{7}{{11}}} \right)\)

\(\begin{array}{l} = \left( {\frac{{2.11.4}}{{3.11.4}} - \frac{{5.3.4}}{{11.3.4}} + \frac{{1.3.11}}{{4.3.11}}} \right):\left( {\frac{11.12}{11.12} + \frac{{5.11}}{{12.11}} - \frac{{7.12}}{{11.12}}} \right)\\ = \left( {\frac{{88 - 60 + 33}}{{121}}} \right):\left( { \frac{{121+55 - 84}}{{121}}} \right)\\ = \frac{{61}}{{121}}:\frac{{92}}{{121}} = \frac{{61}}{{121}}.\frac{{121}}{{92}}= \frac{{61}}{{92}}\end{array}\)

c) \(\left( {13,6 - 37,8} \right).\left( { - 3,2} \right)\)

\( = \left( { - 24,2} \right).\left( { - 3,2} \right) = 77,44\)

d) \(\left( { - 25,4} \right).\left( {18,5 + 43,6 - 16,8} \right):12,7\)

\(\begin{array}{l} = \left( { - 25,4} \right).\left( {62,1 - 16,8} \right):12,7\\ = \left( { - 25,4} \right).45,3:12,7\\ = \left( { - 25,4} \right):12,7.45,3\\ =  (- 2).45,3 =  - 90,6\end{array}\)

a: \(=\dfrac{2}{5}\cdot\left(-\dfrac{3}{7}-\dfrac{5}{14}\right)-\dfrac{18}{35}\)

\(=\dfrac{2}{5}\cdot\dfrac{-6-5}{14}-\dfrac{18}{35}\)

\(=\dfrac{2}{5}\cdot\dfrac{-11}{14}-\dfrac{18}{35}=-\dfrac{22}{70}-\dfrac{18}{35}=\dfrac{-58}{70}=-\dfrac{29}{35}\)

b: \(=\dfrac{88-60+33}{132}:\dfrac{132+55-84}{132}\)

\(=\dfrac{61}{132}\cdot\dfrac{132}{103}=\dfrac{61}{103}\)

c: \(=-24.2\cdot\left(-3.2\right)=24.2\cdot3.2=77.44\)

d: \(=\dfrac{-25.4}{12.7}\cdot45.3=-2\cdot45.3=-90.6\)

14 tháng 4 2017

khó thấy quá bạn ơi

21 tháng 4 2016

a)\(19\frac{5}{8}:\frac{7}{12}-15\frac{1}{4}:\frac{7}{12}\)

=(\(19\frac{5}{8}-15\frac{1}{4}\)):\(\frac{7}{12}\)

=(\(19\frac{10}{16}-15\frac{4}{16}\)):\(\frac{7}{12}\)

=\(4\frac{6}{16}:\frac{7}{12}\)

=\(\frac{35}{8}:\frac{7}{12}\)

=\(\frac{35}{8}\cdot\frac{12}{7}\)

=\(\frac{15}{2}\)

b)2/5*1/3-2/15:1/5+3/5*1/3

=2/15-2/3+1/5

=-8/15+1/5

=-1/3

aidi qua dong tinh nho h chom minh nhe

23 tháng 2 2021

mik ko hieu lam