đấy nhá

b) Ta có: \(\left|x\right|-\dfrac{3}{4}=\dfrac{5}{3}\)

\(\Leftrightarrow\left|x\right|=\dfrac{5}{3}+\dfrac{3}{4}=\dfrac{20}{12}+\dfrac{9}{12}=\dfrac{29}{12}\)

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{29}{12}\\x=-\dfrac{29}{12}\end{matrix}\right.\)

c) Ta có: \(\left|2x-\dfrac{1}{3}\right|+\dfrac{5}{6}=1\)

\(\Leftrightarrow\left|2x-\dfrac{1}{3}\right|=\dfrac{1}{6}\)

\(\Leftrightarrow\left[{}\begin{matrix}2x-\dfrac{1}{3}=\dfrac{1}{6}\\2x-\dfrac{1}{3}=\dfrac{-1}{6}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=\dfrac{1}{6}+\dfrac{1}{3}=\dfrac{1}{2}\\2x=\dfrac{1}{6}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{4}\\x=\dfrac{1}{12}\end{matrix}\right.\)

=>x-1/2=3+1/14-5-1/3-4/7+11/21

=>x-1/2=-97/42

=>x-21/42=-97/42

=>x=-97/42+21/42=-76/42=-38/21

a) x=4/2

b) x=1/12

c) 24/35

a,\(\dfrac{1}{2}+x=\dfrac{5}{2}\)

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

\(\Rightarrow x=2\)

b,\(\dfrac{3}{4}-x=\dfrac{2}{3}\)

\(x=\dfrac{3}{4}-\dfrac{2}{3}\)

\(\Rightarrow x=\dfrac{1}{12}\)

c,\(x:\dfrac{4}{5}=\dfrac{6}{7}\)

\(x=\dfrac{6}{7}.\dfrac{4}{5}\)

\(\Rightarrow\dfrac{24}{35}\)

a)1/2+x=5/2                                          b)3/4-x=2/3

    x=5/2-1/2=4/2=2                                  x=3/4-2/3=1/12

c)x:4/5=6/7

   x=6/7.4/5=24/35

\(x+7\dfrac{4}{5}=9\dfrac{7}{15}\)

\(=>x+\dfrac{39}{5}=\dfrac{142}{15}\)

\(=>x=\dfrac{142}{15}-\dfrac{39}{5}=\dfrac{142}{15}-\dfrac{117}{15}\)

\(=>x=\dfrac{25}{15}=\dfrac{5}{3}\)

___________

\(x-4\dfrac{9}{11}=\dfrac{2121}{2222}\)

\(=>x-\dfrac{53}{11}=\dfrac{21}{22}\)

\(=>x=\dfrac{21}{22}+\dfrac{53}{11}=\dfrac{21}{22}+\dfrac{106}{22}\)

\(=>x=\dfrac{127}{22}\)

\(x+7\dfrac{4}{5}=9\dfrac{7}{15}\)

\(x=9\dfrac{7}{15}-7\dfrac{4}{5}\)

\(x=\left(9-7\right)+\left(\dfrac{7}{15}-\dfrac{4}{5}\right)\)

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

\(x=\dfrac{2121:101}{2222:101}+4\dfrac{9}{11}\)

\(x=\dfrac{21}{22}+4\dfrac{18}{22}\)

\(x=\dfrac{21+4\cdot22+18}{22}=\dfrac{127}{22}\)

a) \(x=\dfrac{-2}{7}+\dfrac{9}{7}=1\) 

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

     \(\dfrac{x}{3}=\dfrac{-14}{15}\) 

\(\Rightarrow x=\dfrac{3.-14}{15}=\dfrac{-14}{5}\)

\(x=\dfrac{-2}{7}+\dfrac{9}{7}\) 

\(x=1\)

x=1

\(\dfrac{-4}{x}=\dfrac{x}{-49}\\ \Rightarrow x^2=\left(-4\right)\left(-49\right)\\ \Rightarrow x^2=196\\ \Rightarrow x=\pm14\)

\(\dfrac{3.6}{x-3}=\dfrac{5}{3}\\ \Rightarrow5\left(x-3\right)=3.3.6\\ \Rightarrow5\left(x-3\right)=54\\ \Rightarrow x-3=\dfrac{54}{5}\\ \Rightarrow x=\dfrac{54}{5}+3\\ \Rightarrow x=\dfrac{69}{15}\)

\(\left(2x+1\right):2=12:3\\ \left(2x+1\right):2=4\\2x+1=2\\ 2x=1\\ x=\dfrac{1}{2} \)

\(\left(2x-14\right):3=12:9\\ \left(2x-14\right):3=\dfrac{4}{3}\\ 2x-14=4\\ 2x=16\\ x=8\)

\(\dfrac{9}{5}-\dfrac{3}{4}:\dfrac{5}{6}=\dfrac{9}{5}-\dfrac{9}{10}=\dfrac{9}{10}\)

\(x=\dfrac{7}{9}:\dfrac{5}{7}=\dfrac{49}{45}\)

\(=\dfrac{9}{5}-\dfrac{3}{4}x\dfrac{6}{5}=\dfrac{9}{5}-\dfrac{9}{10}=\dfrac{18}{10}-\dfrac{9}{10}=\dfrac{9}{10}\)

\(x=\dfrac{7}{9}:\dfrac{5}{7}\)

\(x=\dfrac{49}{45}\)

9/5-3/4:5/6=9/5-9/10=9/10

7/9:x=5/7

x=7/9:5/7

x=49/45

a, \(x\) : \(\dfrac{13}{3}\) = -2,5

    \(x\)         = -2,5 . \(\dfrac{13}{3}\)

    \(x\)         = \(\dfrac{65}{6}\)

b,\(\dfrac{3}{5}\)\(x\)         = \(\dfrac{1}{10}-\)\(\dfrac{1}{4}\)

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

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

      \(x\)          = \(\dfrac{-1}{4}\)

c, \(\dfrac{25}{9}-\dfrac{12}{13}x=\dfrac{7}{9}\)

              \(\dfrac{12}{13}x\)\(=\dfrac{25}{9}-\dfrac{7}{9}\)

               \(\dfrac{12}{13}x=2\)

                    \(x=2:\dfrac{12}{13}\)

                    \(x=\dfrac{13}{6}\)