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16 tháng 9 2018

\(\left(-0,75x+\frac{5}{2}\right).\frac{7}{4}-\left(\frac{-1}{3}\right)=\frac{-5}{7}\)

\(\left(-0,75x+\frac{5}{2}\right).\frac{7}{4}=\frac{-5}{7}+\left(\frac{-1}{3}\right)\)

\(\left(-0,75x+\frac{5}{2}\right).\frac{7}{4}=\frac{-22}{21}\)

\(-0,75x+\frac{5}{2}=\frac{-22}{21}:\frac{7}{4}\)

\(-0,75x+\frac{5}{2}=\frac{-88}{147}\)

\(-0,75x=\frac{-88}{147}-\frac{5}{2}\)

\(-0,75x=\frac{-911}{294}\)

\(x=\frac{-911}{294}:\left(-0,75\right)\)

\(x=\frac{1822}{441}\)

29 tháng 10 2021

3: \(\left|x-\dfrac{3}{4}\right|-\dfrac{1}{2}=0\)

\(\Leftrightarrow\left|x-\dfrac{3}{4}\right|=\dfrac{1}{2}\)

\(\Leftrightarrow\left[{}\begin{matrix}x-\dfrac{3}{4}=\dfrac{1}{2}\\x-\dfrac{3}{4}=-\dfrac{1}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{4}\\x=\dfrac{1}{4}\end{matrix}\right.\)

x xấp xỉ =6,05

hok tốt

18 tháng 6 2019

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

\(\left(-\frac{3}{4}x+\frac{5}{2}\right)\cdot\frac{4}{7}=-\frac{7}{6}\\ \left(-\frac{3}{4}x+\frac{5}{2}\right)=-\frac{7}{6}:\frac{4}{7}=-\frac{49}{24}\\ -\frac{3}{4}x=-\frac{49}{24}-\frac{5}{2}\)

\(-\frac{3}{4}x=-\frac{109}{24}\\ x=-\frac{109}{24}:-\frac{3}{4}=\frac{109}{18}\)

\(A-B=\left(1+\dfrac{3}{4}-\dfrac{3}{4}\right)x^4+\left(-\dfrac{1}{8}x^3+\dfrac{1}{8}x^3\right)+\left(-\dfrac{5}{4}+\dfrac{9}{4}\right)x^2+\left(\dfrac{2}{5}x-\dfrac{2}{5}x\right)+\dfrac{4}{7}+\dfrac{3}{7}\)

\(=x^4+x^2+1>0\forall x\)

17 tháng 9 2023

e tách ra nhé.☘

17 tháng 9 2023

;))

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

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

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

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

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

27 tháng 9

Bài 1:

a; \(\dfrac{7}{8}\) + \(x\) = \(\dfrac{4}{7}\)

     \(x\) = \(\dfrac{4}{7}\) - \(\dfrac{7}{8}\)

     \(x\) = \(\dfrac{32}{56}\) - \(\dfrac{49}{56}\)

     \(x=-\) \(\dfrac{49}{56}\)

Vậy \(x=-\dfrac{49}{56}\)

b; 6 - \(x\) = - \(\dfrac{3}{4}\)

         \(x\) = 6 + \(\dfrac{3}{4}\)

         \(x\) = \(\dfrac{24}{4}+\dfrac{3}{4}\)

         \(x=\dfrac{27}{4}\)

Vậy \(x=\dfrac{27}{4}\) 

c; \(\dfrac{1}{-5}\) + \(x\) = \(\dfrac{3}{4}\)

              \(x\) = \(\dfrac{3}{4}\) + \(\dfrac{1}{5}\)

              \(x=\dfrac{15}{20}\) + \(\dfrac{4}{20}\)

               \(x=\dfrac{19}{20}\)

Vậy \(x=\dfrac{19}{20}\) 

27 tháng 9

      Bài 1:

d; - 6 - \(x\) = - \(\dfrac{3}{5}\)

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

       \(x=-\dfrac{30}{5}\) + \(\dfrac{3}{5}\)

       \(x=-\dfrac{27}{5}\)

Vậy \(x=-\dfrac{27}{5}\)

e; - \(\dfrac{2}{6}\) + \(x\) = \(\dfrac{5}{7}\)

             \(x\) = \(\dfrac{5}{7}\) + \(\dfrac{2}{6}\)

             \(x\) = \(\dfrac{15}{21}\) + \(\dfrac{1}{3}\)

              \(x=\dfrac{15}{21}\) + \(\dfrac{7}{21}\)

               \(x=\dfrac{22}{21}\)

Vậy \(x=\dfrac{22}{21}\) 

f; - 8 - \(x\) =  - \(\dfrac{5}{3}\)

          \(x\) = \(-\dfrac{5}{3}\) + 8

         \(x\) = \(\dfrac{-5}{3}\) + \(\dfrac{24}{3}\)

         \(x\) = \(\dfrac{-19}{3}\)

Vậy \(x=-\dfrac{19}{3}\) 

 

            

 

14 tháng 10 2019