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\(a,|x-\frac{1}{3}|+\frac{4}{5}=|-3,2+\frac{2}{5}|\)

\(\Rightarrow|x-\frac{1}{3}|+\frac{4}{5}=|-\frac{7}{10}|\)

\(\Rightarrow|x-\frac{1}{3}|+\frac{4}{5}=\frac{7}{10}\)

\(\Rightarrow|x-\frac{1}{3}|=\frac{7}{10}-\frac{4}{5}\)

\(\Rightarrow|x-\frac{1}{3}|=-\frac{1}{10}\)

\(\Rightarrow\orbr{\begin{cases}x-\frac{1}{3}=\frac{1}{10}\\x-\frac{1}{3}=-\frac{1}{10}\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{13}{30}\\x=\frac{7}{30}\end{cases}}\)

26 tháng 6 2017

\(\frac{3}{2}x-\frac{2}{3}=\frac{2}{3}:\frac{3}{2}\)

\(\frac{3}{2}x-\frac{2}{3}=\frac{4}{9}\)

\(\frac{3}{2}x=\frac{4}{9}+\frac{2}{3}\)

\(\frac{3}{2}x=\frac{10}{9}\)

\(x=\frac{10}{9}:\frac{3}{2}\)

\(x=\frac{20}{27}\)

Vậy x=\(\frac{20}{27}\)

\(\left(\frac{9}{11}-x\right):\frac{-10}{11}=1-\frac{4}{5}\)

\(\left(\frac{9}{11}-x\right):\frac{-10}{11}=\frac{1}{5}\)

\(\frac{9}{11}-x=\frac{1}{5}\cdot\frac{-10}{11}\)

\(\frac{9}{11}-x=\frac{-2}{11}\)

\(x=\frac{9}{11}-\frac{-2}{11}\)

\(x=1\)

Vậy x=1

\(\frac{-11}{12}\cdot x+\frac{3}{4}=\frac{-1}{6}\)

\(\frac{-11}{12}\cdot x=\frac{-1}{6}-\frac{3}{4}\)

\(\frac{-11}{12}\cdot x=\frac{21}{12}\)

\(x=\frac{-21}{11}\)

Vậy x=\(\frac{-21}{11}\)

\(\frac{-5}{4}-\left(1\frac{1}{2}+x\right)=4,5\)

\(\frac{3}{2}+x=\frac{-5}{4}-\frac{9}{2}\)

\(\frac{3}{2}+x=\frac{23}{4}\)

\(x=\frac{17}{4}\)

Vậy x=\(\frac{17}{4}\)

\(\left(\frac{3}{4}-x:\frac{2}{15}\right)\cdot\frac{1}{5}=-2,6\)

\(\frac{3}{4}-x:\frac{2}{15}=\frac{-13}{5}:\frac{1}{5}\)

\(\frac{3}{4}-x:\frac{2}{15}=-13\)

\(x:\frac{2}{15}=\frac{3}{4}-\left(-13\right)\)

\(x:\frac{2}{15}=\frac{45}{4}\)

\(x=\frac{3}{2}\)

Vậy x=\(\frac{3}{2}\)

\(3-\left(\frac{1}{6}-x\right)\cdot\frac{2}{3}=\frac{2}{3}\)

\(3-\left(\frac{1}{6}-x\right)=\frac{2}{3}:\frac{2}{3}\)

\(3-\left(\frac{1}{6}-x\right)=1\)

\(\frac{1}{6}-x=2\)

\(x=\frac{1}{6}-2\)

\(x=\frac{-11}{6}\)

Vậy x=\(\frac{-11}{6}\)

\(\left(1-2x\right)\cdot\frac{4}{5}=\left(-2\right)^3\)

\(1-2x=\frac{-1}{10}\)

\(2x=1-\frac{-1}{10}\)

\(2x=\frac{11}{10}\)

\(x=\frac{11}{20}\)

Vậy x=\(\frac{11}{20}\)

\(\frac{1}{6}-\left|\frac{1}{2}\cdot x-\frac{1}{3}\right|=\frac{1}{8}\)

\(\left|\frac{1}{2}\cdot x-\frac{1}{3}\right|=\frac{7}{12}\)

\(\Rightarrow\frac{1}{2}x-\frac{1}{3}=\frac{7}{12}\)                                                         \(\frac{1}{2}x-\frac{1}{3}=\frac{-7}{12}\)

\(\frac{1}{2}x=\frac{11}{12}\)                                                                        \(\frac{1}{2}x=\frac{-1}{4}\)

\(x=\frac{11}{6}\)                                                                              \(x=\frac{-1}{2}\)

Vậy \(x\in\left\{\frac{11}{6};\frac{-1}{2}\right\}\)

26 tháng 6 2017

\(\frac{3}{2}x-\frac{2}{3}=\frac{2}{3}:\frac{3}{2}\)

\(\frac{3}{2}x=\frac{4}{9}+\frac{6}{9}\)

\(\frac{3}{2}x=\frac{10}{9}\)

\(x=\frac{10}{9}:\frac{3}{2}\)

\(x=\frac{20}{27}\)

tk mình đi mình làm nốt cho hjhj ^^

24 tháng 7 2020

\(B=\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+\frac{1}{5^2}+\frac{1}{6^2}+\frac{1}{7^2}+\frac{1}{8^2}\)

Ta có : \(\frac{1}{2^2}=\frac{1}{2\cdot2}< \frac{1}{1\cdot2}\)

\(\frac{1}{3^2}=\frac{1}{3\cdot3}< \frac{1}{2\cdot3}\)

...

\(\frac{1}{8^2}=\frac{1}{8\cdot8}< \frac{1}{7\cdot8}\)

Cộng vế theo vế 

\(\Rightarrow B=\frac{1}{2^2}+\frac{1}{3^2}+...+\frac{1}{8^2}< \frac{1}{1\cdot2}+\frac{1}{2\cdot3}+...+\frac{1}{7\cdot8}\)

\(\Rightarrow B< \frac{1}{1}-\frac{1}{8}=\frac{7}{8}\)

Lại có \(\frac{7}{8}< 1\)

Theo tính chất bắc cầu => \(B< \frac{7}{8}< 1\)

\(\Rightarrow B< 1\left(đpcm\right)\)

10 tháng 4 2016

\(x=\frac{903}{391}\)

Bài này sử dụng MTCT đó bạn!

10 tháng 4 2016

903/391 mình nghĩ vậy

6 tháng 6 2016

a) (1/2(2/− 2x0

\(\Rightarrow\left[\begin{array}{nghiempt}x+\frac{1}{2}=0\\\frac{2}{3}-2x=0\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}x=-\frac{1}{2}\\2x=\frac{2}{3}\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}x=-\frac{1}{2}\\x=\frac{1}{3}\end{array}\right.\)

b) \(\left(x.6\frac{2}{7}+\frac{3}{7}\right).2\frac{1}{5}-\frac{3}{7}=-2\)

\(\Rightarrow\left(x.\frac{44}{7}+\frac{3}{7}\right).\frac{11}{5}=-2+\frac{3}{7}\)

\(\Rightarrow\left(x.\frac{44}{7}+\frac{3}{7}\right).\frac{11}{5}=-\frac{11}{7}\)

\(\Rightarrow x.\frac{44}{7}+\frac{3}{7}=-\frac{11}{7}:\frac{11}{5}=-\frac{11}{7}.\frac{5}{11}\)

\(\Rightarrow x.\frac{44}{7}+\frac{3}{7}=-\frac{5}{7}\)

\(\Rightarrow x.\frac{44}{7}=-\frac{5}{7}-\frac{3}{7}\)

\(\Rightarrow x.\frac{44}{7}=-\frac{8}{7}\)

\(\Rightarrow x=-\frac{8}{7}:\frac{44}{7}=-\frac{8}{7}.\frac{7}{44}\)

\(\Rightarrow x=-\frac{2}{11}\)

6 tháng 6 2016

c) \(x.3\frac{1}{4}+\left(-\frac{7}{6}\right).x-1\frac{2}{3}=\frac{5}{12}\)

\(\Rightarrow x\left(3\frac{1}{4}-\frac{7}{6}\right)=\frac{5}{12}+\frac{5}{3}\)

\(\Rightarrow x\left(\frac{13}{4}-\frac{7}{6}\right)=\frac{25}{12}\)

\(\Rightarrow x.\frac{25}{12}=\frac{25}{12}\)

\(\Rightarrow x=\frac{25}{12}:\frac{25}{12}\)

\(\Rightarrow x=1\)

d) \(5\frac{8}{17}:x+\left(-\frac{4}{17}\right):x+3\frac{1}{7}:17\frac{1}{3}=\frac{4}{11}\)

\(\Rightarrow\left(5\frac{8}{17}-\frac{4}{17}\right):x+\frac{22}{7}:\frac{52}{3}=\frac{4}{11}\)

\(\Rightarrow5\frac{4}{17}:x+\frac{33}{182}=\frac{4}{11}\)

\(\Rightarrow\frac{89}{17}:x=\frac{4}{11}-\frac{33}{182}\)

\(\Rightarrow\frac{89}{17}:x=\frac{365}{2002}\)

\(\Rightarrow x=\frac{89}{17}:\frac{365}{2002}\)

\(\Rightarrow x\approx28,7\) (số hơi lẻ)

e) \(\frac{17}{2}-\left|2x-\frac{3}{4}\right|=-\frac{7}{4}\)

\(\Rightarrow\left|2x-\frac{3}{4}\right|=\frac{17}{2}+\frac{7}{4}\)

\(\Rightarrow\left|2x-\frac{3}{4}\right|=\frac{41}{4}\)

\(\Rightarrow\left[\begin{array}{nghiempt}2x-\frac{3}{4}=\frac{41}{4}\\2x-\frac{3}{4}=-\frac{41}{4}\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}2x=11\\2x=-\frac{19}{2}\end{array}\right.\)

\(\Rightarrow\left[\begin{array}{nghiempt}x=\frac{11}{2}\\x=-\frac{19}{4}\end{array}\right.\)

26 tháng 8 2017

kb lqmb vs mk ko mk là P.A.D8a1

26 tháng 8 2017

Làm hết thì đã lên " THÁNH "