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2 tháng 12 2022

24/31 : (2/31:3)

=24/31:2/93

=36

(12/15:2):(3/30:2)

=2/5:1/20

=8

8 tháng 5 2022

`a)1/2+[-1]/[-3]-5/12 < 2x < 12/[-31]+136/31`

`186/372+124/372-155/372 < [744x]/372 < [-144]/372+1632/372`

`186+124-155 < 744x < -144+1632`

`155 < 744x < 1488`

`155:744 < 744x:744 < 1488:744`

`5/24 < x < 2`

Vậy `5/24 < x < 2`

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`b)[-2]/5 < x/15 < 1/6`

`[-12]/30 < [2x]/30 < 5/30`

`-12 < 2x < 5`

`-12:2 < 2x:2 < 5:2`

`-6 < x < 5/2`

Vậy `-6 < x < 5/2`

8 tháng 5 2022

Giải:

a) x - \(\dfrac{9}{25}\)\(\dfrac{16}{25}\)

x = \(\dfrac{16}{25}\)+\(\dfrac{9}{25}\)
x = \(\dfrac{25}{25}\)

x = 1

b) \(\dfrac{-12}{30}\)<\(\dfrac{x}{30}\)<\(\dfrac{5}{30}\)

=> x có thể bằng \(\dfrac{-11}{30}\) đến \(\dfrac{4}{30}\)
=> x bằng -5; -4; -3; -2; -1;0;1;2

16 tháng 7 2023

\(\dfrac{2}{5}\times15\dfrac{1}{3}-\dfrac{2}{5}\times10\dfrac{1}{3}\)

\(=\dfrac{2}{5}\times\left(15\dfrac{1}{3}-10\dfrac{1}{3}\right)\)

\(=\dfrac{2}{5}\times5\)

\(=2\)

____________________

\(12\dfrac{5}{11}-\left(3\dfrac{1}{4}+2\dfrac{5}{11}\right)\)

\(=12\dfrac{5}{11}-3\dfrac{1}{4}-2\dfrac{5}{11}\)

\(=\left(12\dfrac{5}{11}-2\dfrac{5}{11}\right)-3\dfrac{1}{4}\)

\(=10-3\dfrac{1}{4}\)

\(=\dfrac{27}{4}\)

_______________

\(\dfrac{34}{31}-\dfrac{19}{28}-\dfrac{3}{31}\)

\(=\left(\dfrac{34}{31}-\dfrac{3}{31}\right)-\dfrac{19}{28}\)

\(=\dfrac{31}{31}-\dfrac{19}{28}\)

\(=1-\dfrac{19}{28}\)

\(=\dfrac{9}{28}\)

\(\Leftrightarrow-\dfrac{16}{279}< \dfrac{x}{9}< =\dfrac{2}{3}\)

\(\Leftrightarrow\dfrac{x}{9}=0\)

hay x=0

=>\(1\cdot\dfrac{2}{4}\cdot\dfrac{3}{6}\cdot...\cdot\dfrac{31}{62}\cdot\dfrac{1}{64}=2^x\)

=>\(2^x=\dfrac{1}{2}\cdot\dfrac{1}{2}\cdot...\cdot\dfrac{1}{2}\cdot\dfrac{1}{64}=\left(\dfrac{1}{2}\right)^{30}\cdot\left(\dfrac{1}{2}\right)^6=\dfrac{1}{2^{36}}\)

=>x=-36

22 tháng 3 2018

A=1

bấm máy tính cx thấy mệt luôn!!!oaoa

22 tháng 3 2018

thương nhiuhaha

\(\dfrac{1}{2.2}.\dfrac{2}{2.3}.....\dfrac{31}{64}=2^x\\ =>\dfrac{1}{2.2.2.....2.64}=2^x\\ \dfrac{1}{2^{30}.26}=2^x\\ =>\dfrac{1}{2^{36}}=2^x\\ =>2^{-36}=2^x\\ =>x=-36\)

6 tháng 8 2021

\(n=-36\)

23 tháng 4 2023

1) \(\dfrac{1}{2}+\dfrac{13}{19}-\dfrac{4}{9}+\dfrac{6}{19}+\dfrac{5}{18}\)

\(=\dfrac{1}{2}+\left(\dfrac{13}{19}+\dfrac{6}{19}\right)-\dfrac{4}{9}+\dfrac{5}{18}\)

\(=\dfrac{3}{2}-\dfrac{4}{9}+\dfrac{5}{18}\)

\(=\dfrac{19}{18}+\dfrac{5}{18}\)

\(=\dfrac{24}{18}\)

\(=\dfrac{4}{3}\)

2) \(\dfrac{-20}{23}+\dfrac{2}{3}-\dfrac{3}{23}+\dfrac{2}{5}+\dfrac{7}{15}\)

\(=\left(-\dfrac{20}{23}-\dfrac{3}{23}\right)+\dfrac{2}{3}+\dfrac{2}{5}+\dfrac{7}{15}\)

\(=-1+\dfrac{2}{3}+\dfrac{2}{5}+\dfrac{7}{15}\)

\(=-\dfrac{1}{3}+\dfrac{2}{5}+\dfrac{7}{15}\)

\(=\dfrac{1}{15}+\dfrac{7}{15}\)

\(=\dfrac{8}{15}\)

3) \(\dfrac{4}{3}+\dfrac{-11}{31}+\dfrac{3}{10}-\dfrac{20}{31}-\dfrac{2}{5}\)

\(=\left(\dfrac{-11}{31}-\dfrac{20}{31}\right)+\dfrac{4}{3}+\dfrac{3}{10}-\dfrac{2}{5}\)

\(=-1+\dfrac{4}{3}+\dfrac{3}{10}-\dfrac{2}{5}\)

\(=\dfrac{1}{3}+\dfrac{3}{10}-\dfrac{2}{5}\)

\(=\dfrac{1}{3}-\dfrac{1}{10}\)

\(=\dfrac{7}{30}\)

4) \(\dfrac{5}{7}.\dfrac{5}{11}+\dfrac{5}{7}.\dfrac{2}{11}-\dfrac{5}{7}.\dfrac{14}{11}\)

\(=\dfrac{5}{7}.\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)\)

\(=\dfrac{5}{7}.-\dfrac{7}{11}\)

\(=-\dfrac{35}{77}\)

\(=-\dfrac{5}{11}\)

21 tháng 3 2018

A=\(\left[\dfrac{\dfrac{42}{31}.\dfrac{31}{7}-\left(15-\dfrac{2}{3}\right)}{\dfrac{29}{6}+\dfrac{1}{6}.\dfrac{20}{3}}\right].\dfrac{31}{50}\)

= \(\left(\dfrac{6-\dfrac{43}{3}}{\dfrac{29}{6}+\dfrac{10}{9}}\right).\dfrac{31}{50}\)=\(\left(\dfrac{\dfrac{-25}{3}}{\dfrac{107}{18}}\right).\dfrac{31}{50}\)=\(\dfrac{-150}{107}.\dfrac{31}{50}\)=\(\dfrac{-93}{107}\)

16 tháng 9 2023

\(a,MSC:180\\ \dfrac{17}{12}=\dfrac{17.15}{12.15}=\dfrac{255}{180};\dfrac{31}{18}=\dfrac{31.10}{18.10}=\dfrac{310}{180};\dfrac{8}{15}=\dfrac{8.12}{15.12}=\dfrac{96}{180}\\ b,MSC:75\\ \dfrac{7}{15}=\dfrac{7.5}{15.5}=\dfrac{35}{75};\dfrac{8}{25}=\dfrac{8.3}{25.3}=\dfrac{24}{75};\dfrac{11}{75}=\dfrac{11}{75}\)