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2 tháng 8 2020

a ) \(\frac{3}{7}-\left(\frac{2}{5}+x+\frac{3}{2}\right)=\frac{5}{14}-\left|\frac{4}{35}-\frac{\left(-11\right)}{70}\right|\)

=> \(\frac{3}{7}-\left(\frac{2}{5}+x+\frac{3}{2}\right)=\frac{5}{14}-\left|\frac{4}{35}+\frac{11}{70}\right|\)

=> \(\frac{3}{7}-\left(\frac{2}{5}+x+\frac{3}{2}\right)=\frac{5}{14}-\left|\frac{19}{70}\right|\)

=> \(\frac{3}{7}-\left(\frac{2}{5}+x+\frac{3}{2}\right)=\frac{5}{14}-\frac{19}{70}=\frac{3}{35}\)

=> \(\frac{2}{5}+x+\frac{3}{2}=\frac{3}{7}-\frac{3}{35}=\frac{12}{35}\)

=> \(\frac{2}{5}+x=\frac{12}{35}-\frac{3}{2}=-\frac{81}{70}\)

=> \(x=-\frac{81}{70}-\frac{2}{5}=-\frac{109}{70}\)

b) \(\frac{3}{4}\left(x-8\right)=\frac{5}{7}\left(4-\frac{1}{2}\right)\)

=> \(\frac{3}{4}x-6=\frac{5}{2}\)

=> \(\frac{3}{4}x=\frac{17}{2}\)

=> \(x=\frac{17}{2}:\frac{3}{4}=\frac{34}{3}\)

Câu c,d tự làm nhé

2 tháng 8 2020

a. \(\frac{3}{7}-\left(\frac{2}{5}+x+\frac{3}{2}\right)=\frac{5}{14}-\left|\frac{4}{35}-\frac{-11}{70}\right|\)

\(\Rightarrow\frac{3}{7}-\left(\frac{19}{10}+x\right)=\frac{5}{14}-\left|\frac{4}{35}+\frac{11}{70}\right|\)

\(\Rightarrow\frac{3}{7}-\frac{19}{10}-x=\frac{5}{14}-\left|\frac{19}{70}\right|=\frac{5}{14}-\frac{19}{70}\)

\(\Rightarrow-\frac{103}{70}-x=\frac{3}{35}\)

\(\Rightarrow x=-\frac{103}{70}-\frac{3}{35}\)

\(\Rightarrow x=-\frac{109}{70}\)

b. \(\frac{3}{4}\left(x-8\right)=\frac{5}{7}\left(4-\frac{1}{2}\right)\)

\(\Rightarrow\frac{3}{4}\left(x-8\right)=\frac{5}{7}.\frac{7}{2}=\frac{5}{2}\)

\(\Rightarrow x-8=\frac{10}{3}\)

\(\Rightarrow x=\frac{34}{3}\)

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

\(\Rightarrow\frac{3}{2}-1+4x=\frac{2}{3}-7x\)

\(\Rightarrow\frac{1}{2}=\frac{2}{3}-7x-4x=\frac{2}{3}-11x\)

\(\Rightarrow11x=\frac{2}{3}-\frac{1}{2}=\frac{1}{6}\)

\(\Rightarrow x=\frac{1}{66}\)

d. \(4\left(\frac{1}{2}-x\right)-5\left(x-\frac{3}{10}\right)=\frac{7}{4}\)

\(\Rightarrow2-4x-5x+\frac{3}{2}=\frac{7}{4}\)

\(\Rightarrow2-9x=\frac{1}{4}\)

\(\Rightarrow9x=\frac{7}{4}\)

\(\Rightarrow x=\frac{7}{36}\)

28 tháng 3 2020

\(a,x.\frac{-3}{7}=\frac{4}{21}\)

\(x=\frac{4}{21}:\frac{-3}{7}\)

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

\(b,\frac{-4}{7}:x=\frac{2}{5}\)

\(x=\frac{-4}{7}:\frac{2}{5}\)

\(x=\frac{-10}{7}\)

\(c,x+\frac{1}{12}=\frac{-3}{8}\)

\(x=\frac{-3}{8}-\frac{1}{12}\)

\(x=\frac{-11}{24}\)

\(d,\frac{2}{15}-x=\frac{-3}{10}\)

\(x=\frac{2}{15}+\frac{3}{10}\)

\(x=\frac{13}{30}\)

28 tháng 3 2020

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

\(-x=\frac{-3}{10}\)

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

\(f,\frac{3}{4}.\left(x+1\right)-\frac{1}{2}=\frac{3}{7}\)

\(\frac{3}{4}.\left(x+1\right)=\frac{13}{14}\)

\(x+1=\frac{26}{21}\)

\(x=\frac{5}{21}\)

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

\(\frac{-3}{2}-2x=\frac{-11}{4}\)

\(2x=\frac{-3}{2}+\frac{11}{4}\)

\(2x=\frac{-17}{4}\)

\(x=\frac{-17}{8}\)

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

\(-x=\frac{-3}{10}\)

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

chúc bạn học tốt !!!

15 tháng 10 2019

3) \(\frac{x-3}{x-2}=\frac{4}{7}\)

\(\Rightarrow\left(x-3\right).7=\left(x-2\right).4\)

\(\Rightarrow7x-21=4x-8\)

\(\Rightarrow7x-4x=\left(-8\right)+21\)

\(\Rightarrow3x=13\)

\(\Rightarrow x=13:3\)

\(\Rightarrow x=\frac{13}{3}\)

Vậy \(x=\frac{13}{3}.\)

4) \(\left|x\right|+3,5=0\)

\(\Rightarrow\left|x\right|=0-3,5\)

\(\Rightarrow\left|x\right|=-3,5\)

\(\left|x\right|\ge0\) \(\forall x.\)

\(\Rightarrow\left|x\right|>-3,5\)

\(\Rightarrow\left|x\right|\ne-3,5\)

Vậy \(x\in\varnothing.\)

5) \(\left|x+\frac{1}{3}\right|-4=1\)

\(\Rightarrow\left|x+\frac{1}{3}\right|=1+4\)

\(\Rightarrow\left|x+\frac{1}{3}\right|=5.\)

\(\Rightarrow\left[{}\begin{matrix}x+\frac{1}{3}=5\\x+\frac{1}{3}=-5\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=5-\frac{1}{3}\\x=\left(-5\right)-\frac{1}{3}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{14}{3}\\x=-\frac{16}{3}\end{matrix}\right.\)

Vậy \(x\in\left\{\frac{14}{3};-\frac{16}{3}\right\}.\)

Chúc bạn học tốt!

15 tháng 10 2019

Không có gì. vui

Nguyễn Trà My

Phần a)

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

\(32-3x+13=76-x\)

\(116-3x=76-x\)

\(116-76=3x-x\)

\(46=2x\)

\(x=46\div2\)

\(x=13\)

22 tháng 9 2017

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

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

\(\Rightarrow\frac{3}{2}-3x+x=\frac{5}{6}\)

\(-3x+x=\frac{5}{6}-\frac{3}{2}\)

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

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

\(x=-\frac{1}{3}\)

22 tháng 6 2016

\(a,\left(\frac{3}{8}+-\frac{3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)

   =  \(\left(-\frac{3}{8}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)

    = \(\frac{5}{24}:\frac{5}{6}+\frac{1}{2}\)

     = \(\frac{1}{4}+\frac{1}{2}\)

      =  \(\frac{3}{4}\)

b)\(-\frac{7}{3}.\frac{5}{9}+\frac{4}{9}.\left(-\frac{3}{7}\right)+\frac{17}{7}\)

    =\(-\frac{35}{27}+\left(-\frac{4}{21}\right)+\frac{17}{7}\)

   = \(-\frac{35}{27}+\frac{47}{21}\)

   =        \(\frac{178}{189}\)

c) \(\frac{117}{13}-\left(\frac{2}{5}+\frac{57}{13}\right)\)

  = \(\frac{117}{13}-\frac{311}{65}\)

 =       \(\frac{274}{65}\)

d) \(\frac{2}{3}-0,25:\frac{3}{4}+\frac{5}{8}.4\)

\(\frac{2}{3}-\frac{1}{4}:\frac{3}{4}+\frac{5}{8}.4\)

\(\frac{2}{3}-\frac{1}{3}+\frac{5}{2}\)

=     \(\frac{1}{3}+\frac{5}{2}\)

=         \(\frac{17}{6}\)

1) \(\frac{17}{6}-\left(x-\frac{7}{6}\right)=\frac{7}{4}\)

\(\Rightarrow x-\frac{7}{6}=\frac{17}{6}-\frac{7}{4}\)

\(\Rightarrow x=\frac{13}{12}+\frac{7}{6}=\frac{9}{4}\)

2) \(\frac{3}{35}-\left(\frac{3}{5}-x\right)=\frac{2}{7}\)

\(\Rightarrow\)\(\frac{3}{5}-x=\frac{3}{35}-\frac{2}{7}=-\frac{1}{5}\)

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

3) 4) Hjhj^_^^_^

2 tháng 4 2020

1) \(\left|x+\frac{4}{5}\right|+\frac{7}{5}=\frac{3}{5}\)

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

\(\Rightarrow\left|x+\frac{4}{5}\right|=\frac{-4}{5}\)

\(x+\frac{4}{5}=\pm\frac{4}{5}\)

\(TH1:x+\frac{4}{5}=\frac{4}{5}\)

\(\Rightarrow x=\frac{4}{5}-\frac{4}{5}=0\)

\(TH2:x+\frac{4}{5}=\frac{-4}{5}\)

\(\Rightarrow x=\frac{-4}{5}-\frac{4}{5}=\frac{-8}{5}\)

Vậy x ∈ {0; \(\frac{-8}{5}\)}

2 tháng 4 2020

Hỏi đáp ToánHỏi đáp ToánHai câu cuối khó nhìn nên ko giải