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10 tháng 8 2023

a) \(...=-246+301=55\)

b) \(...=-\dfrac{10}{9}+\dfrac{5}{12}=-\dfrac{40}{36}+\dfrac{15}{36}=-\dfrac{25}{36}\)

c) \(...=-\dfrac{3}{26}+\dfrac{24}{69}=-\dfrac{207}{1794}+\dfrac{624}{1794}=\dfrac{417}{1794}\)

17 tháng 8 2023

a, \(\dfrac{1}{2}\) - ( - \(\dfrac{1}{3}\) ) + \(\dfrac{1}{23}\) + \(\dfrac{1}{6}\)

 =  \(\dfrac{5}{6}\)  + \(\dfrac{1}{23}\) + \(\dfrac{1}{6}\)

= 1 + \(\dfrac{1}{23}\)

 = \(\dfrac{24}{23}\) 

b, \(\dfrac{11}{24}\) - \(\dfrac{5}{41}\) + \(\dfrac{13}{24}\) + 0,5 - \(\dfrac{36}{41}\)

= (\(\dfrac{11}{24}\) + \(\dfrac{13}{24}\)) - ( \(\dfrac{5}{41}\) + \(\dfrac{36}{41}\)) + 0,5

= 1 - 1 + 0,5

= 0,5 

 

17 tháng 8 2023

c,\(-\dfrac{1}{12}-\left(\dfrac{1}{6}-\dfrac{1}{4}\right)\)

=\(-\dfrac{1}{12}-\left(-\dfrac{1}{12}\right)\)

=0

d, \(\dfrac{1}{6}-\left[\dfrac{1}{6}-\left(\dfrac{1}{4}+\dfrac{9}{12}\right)\right]\)

\(\dfrac{1}{6}-\left[\dfrac{1}{6}-1\right]\)

\(\dfrac{1}{6}-\left(-\dfrac{5}{6}\right)\)

= 1

10 tháng 8 2023

a) \(0,6+\dfrac{2}{3}=\dfrac{6}{10}+\dfrac{2}{3}=\dfrac{3}{5}+\dfrac{2}{3}=\dfrac{9}{15}+\dfrac{10}{15}=\dfrac{19}{15}\)

b) \(-\dfrac{5}{12}+0,75=-\dfrac{5}{12}+\dfrac{75}{100}=-\dfrac{5}{12}+\dfrac{3}{4}=-\dfrac{5}{12}+\dfrac{9}{12}=\dfrac{4}{12}=\dfrac{1}{3}\)

c) \(\dfrac{1}{3}-\left(-0,4\right)=\dfrac{1}{3}+\dfrac{4}{10}=\dfrac{1}{3}+\dfrac{2}{5}=\dfrac{5}{15}+\dfrac{6}{15}=\dfrac{11}{15}\)

d) \(1\dfrac{3}{5}+\dfrac{5}{6}=\dfrac{8}{5}+\dfrac{5}{6}=\dfrac{48}{40}+\dfrac{25}{30}=\dfrac{73}{30}\)

17 tháng 8 2023

a) \(\dfrac{3}{8}+\dfrac{15}{-25}+\dfrac{3}{5}\)

\(=\dfrac{-9}{40}+\dfrac{3}{5}\)

\(=\dfrac{3}{8}\)

b) \(\dfrac{-5}{18}+\dfrac{23}{45}-\dfrac{9}{10}\)

\(=\dfrac{7}{30}-\dfrac{9}{10}\)

\(=\dfrac{-2}{3}\)

c) \(\dfrac{-5}{12}+\dfrac{15}{18}-2,25\)

\(=\dfrac{5}{12}-2,25\)

\(=\dfrac{-11}{6}\)

d) \(\dfrac{5}{6}+\dfrac{2}{3}-0,5\)

\(=\dfrac{3}{2}-0,5\)

\(=1\)

17 tháng 8 2023

tick cho mink nhé bn ✔

10 tháng 8 2023

\(\dfrac{21}{36}-\left(-\dfrac{11}{30}\right)=\dfrac{7}{12}+\dfrac{11}{30}=\dfrac{7.5+11.2}{60}=\dfrac{57}{60}=\dfrac{19}{20}\\ ----\\\dfrac{-4}{8}+\left(-\dfrac{3}{10}\right)=\dfrac{-1}{2}-\dfrac{3}{10}=\dfrac{-1.5-3}{10}=\dfrac{-8}{10}=-\dfrac{4}{5}\\ ----\\ \dfrac{7}{12}-\left(-\dfrac{9}{20}\right)=\dfrac{7}{12}+\dfrac{9}{20}=\dfrac{7.5+9.3}{60}=\dfrac{62}{60}=\dfrac{31}{30}\\ ---\\ \dfrac{-2}{5}+\left(-\dfrac{11}{30}\right)=-\dfrac{2}{5}-\dfrac{11}{30}=\dfrac{-2.6-11}{30}=-\dfrac{29}{30}\)

16 tháng 8 2023

a) \(\dfrac{13}{20}+\dfrac{3}{5}+x=\dfrac{5}{6}\)

\(\Rightarrow\dfrac{5}{4}+x=\dfrac{5}{6}\)

\(\Rightarrow x=\dfrac{5}{6}-\dfrac{5}{4}\)

\(\Rightarrow x=\dfrac{-5}{12}\)

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

\(\Rightarrow x+\dfrac{1}{3}=\dfrac{11}{15}\)

\(\Rightarrow x=\dfrac{11}{15}-\dfrac{1}{3}\)

\(\Rightarrow x=\dfrac{2}{5}\)

c)\(\dfrac{-5}{8}-x=\dfrac{-3}{20}-\dfrac{-1}{6}\)

\(\dfrac{-5}{8}-x=\dfrac{1}{60}\)

\(\Rightarrow x=\dfrac{-5}{8}-\dfrac{1}{60}\)

\(\Rightarrow x=\dfrac{-77}{120}\)

d) \(\dfrac{3}{5}-x=\dfrac{1}{4}+\dfrac{7}{10}\)

\(\Rightarrow\dfrac{3}{5}-x=\dfrac{19}{20}\)

\(\Rightarrow x=\dfrac{3}{5}-\dfrac{19}{20}\)

\(\Rightarrow x=\dfrac{-7}{20}\)

e) \(\dfrac{-3}{7}-x=\dfrac{4}{5}+\dfrac{-2}{3}\)

\(\Rightarrow\dfrac{-3}{7}-x=\dfrac{2}{15}\)

\(\Rightarrow x=\dfrac{-3}{7}-\dfrac{2}{15}\)

\(\Rightarrow x=\dfrac{-59}{105}\)

16 tháng 8 2023

g) \(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)

\(\Rightarrow\dfrac{-5}{6}-x=\dfrac{1}{4}\)

\(\Rightarrow x=\dfrac{-5}{6}-\dfrac{1}{4}\)

\(\Rightarrow x=\dfrac{-13}{12}\)

31 tháng 7 2023

\([\)6+(\(\dfrac{1}{2}\))3\(]\):\(\dfrac{3}{12}\)=\([\)6+\(\dfrac{1}{8}\)\(]\):\(\dfrac{1}{4}\)=\(\dfrac{49}{8}\):\(\dfrac{1}{4}\)=\(\dfrac{49}{2}\).

27 tháng 6 2023

a, 2\(xy\) - 2\(x\) + 3\(y\) = -9

(2\(xy\) - 2\(x\)) + 3\(y\) - 3 = -12

2\(x\)(\(y-1\)) + 3(\(y-1\)) = -12

(\(y-1\))(2\(x\) + 3) = -12

Ư(12) = {-12; -6; -4; -3; -2; -1; 1; 2; 3; 4; 6; 12}

Lập bảng ta có:

\(y\)-1 -12 -6 -4 -3 -2 -1 1 2 3 4 6 12
\(y\) -11 -5 -3 -2 -1 0 2 3 4 5 7 13
2\(x\)+3 1 2 3 4 6 12 -12 -6 -4 -3 -2 -1
\(x\) -1 -\(\dfrac{1}{2}\) 0 \(\dfrac{1}{2}\) \(\dfrac{3}{2}\) \(\dfrac{9}{2}\) \(-\dfrac{15}{2}\) \(-\dfrac{9}{2}\) -\(\dfrac{7}{2}\) -3 \(-\dfrac{5}{2}\) -2

Theo bảng trên ta có: Các cặp \(x\);\(y\) nguyên thỏa mãn đề bài là:

(\(x;y\)) = (-1; -11); (0; -3); (-3; 5); ( -2; 13)

 

  
 

 

 

          

 

    

27 tháng 6 2023

b, (\(x+1\))2(\(y\) - 3) = -4 

    Ư(4) = {-4; -2; -1; 1; 2; 4}

Lập bảng ta có: 

\(\left(x+1\right)^2\) - 4(loại) -2(loại) -1(loại) 1 2 4
\(x\)       0 \(\pm\)\(\sqrt{2}\)(loại) 1; -3
\(y-3\) 1 2 4 -4 -2 -1
\(y\)       -1   2

Theo bảng trên ta có: các cặp \(x;y\) nguyên thỏa mãn đề bài là: 

(\(x;y\)) = (0; -1); (-3; 2); (1; 2)

 

13 tháng 4 2020

Mọi người ơi giúp mình với

23 tháng 8 2023

a)\(\dfrac{-5}{21}:\dfrac{25}{14}=\dfrac{-5}{21}.\dfrac{14}{25}=\dfrac{-2}{15}\)

b)\(3,4:\dfrac{-17}{14}=\dfrac{17}{15}:\dfrac{-17}{14}=\dfrac{17}{15}.\dfrac{14}{-17}=\dfrac{-14}{15}\)

c) \(\left(-1,7\right):1\dfrac{2}{15}=\dfrac{-17}{10}:\dfrac{17}{15}=\dfrac{-17}{10}.\dfrac{15}{17}=\dfrac{-3}{2}\)

d) \(-8,4:\left(-2,8\right)=\dfrac{-42}{5}:\dfrac{-14}{5}=\dfrac{-42}{5}.\dfrac{5}{-14}=3\)

23 tháng 8 2023

tick cho mình nhé! 😊