\(|2\frac{1}{5}-x|+|x-\frac{1}{5}|+8\frac{1}{5}=1,2\)

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22 tháng 9 2021

1.a) \(\left(31\frac{6}{13}+5\frac{9}{41}\right)-36\frac{6}{13}=\left(31+\frac{6}{13}+5+\frac{9}{41}\right)-\left(36+\frac{6}{13}\right)\)

\(=\left(36+\frac{6}{13}-\frac{9}{41}\right)-\left(36+\frac{6}{13}\right)=\left(36+\frac{6}{13}\right)-\left(36+\frac{6}{13}\right)-\frac{9}{41}=-\frac{9}{41}\)

b) \(\frac{5}{3}+\left(-\frac{2}{7}\right)-\left(-1,2\right)-\left|1.4-0,2\right|\)

\(=\frac{5}{3}-\frac{2}{7}+1,2-1,2=\frac{29}{21}\)

c) \(0,25+\frac{3}{5}-\left(\frac{1}{8}-\frac{2}{5}+1\frac{1}{4}\right)+\left|\frac{3}{5}\right|\)

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

\(=\left(\frac{1}{4}-\frac{1}{4}\right)+\left(\frac{3}{5}+\frac{2}{5}-1\right)+\frac{3}{5}-\frac{1}{8}=\frac{19}{40}\)

2) \(-\frac{3}{5}-x=0,75\)

=> \(-\frac{3}{5}-x=\frac{3}{4}\)

=> \(x=-\frac{3}{5}-\frac{3}{4}=\frac{-27}{20}\)

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

=> \(x+\frac{1}{3}=\frac{2}{5}+\frac{1}{3}\)

=> \(x=\frac{2}{5}\)

c) |2x - 4| + 1 = 5

=> |2x - 4| = 4

<=> \(\orbr{\begin{cases}2x-4=4\\2x-4=-4\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=4\\x=0\end{cases}}\)

Giúp mình với nha cả nhả :<

Cả nhà làm vài ý thui cx được ạ :<

18 tháng 7 2018

a,x-2/5=5/7

x=5/7+2/5

x=39/35

b,-2/5.x=4/15

x=4/15:-2/5

x=-2/3

18 tháng 7 2018

a) \(x-\frac{2}{5}=\frac{5}{7}\)

\(x=\frac{2}{5}+\frac{5}{7}\)

\(x=\frac{14}{35}+\frac{25}{35}=\frac{39}{35}\)

b)

\(\frac{-2}{5}x=\frac{4}{15}\)

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

\(x=\frac{4}{15}\cdot-\frac{5}{2}=-\frac{2}{3}\)

c) \(2x\left(x-\frac{1}{7}\right)=2x^2-\frac{2x}{7}\)

d) \(\frac{1}{2}+\frac{3}{4}x=\frac{1}{4}\)

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

\(\frac{3}{4}x=-\frac{1}{4}\)

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

f) \(\frac{11}{12}-\left(\frac{2}{5}+x\right)=\frac{2}{5}\)

\(\frac{2}{5}+x=\frac{11}{12}-\frac{2}{5}=\frac{31}{60}\)

\(x=\frac{31}{60}-\frac{2}{5}=\frac{7}{60}\)

a: =>x-8/5=1/20-1/10=-1/20

=>x=-0,05+1,6=1,55

b: =>x-3/2=4/3 hoặc x-3/2=-4/3

=>x=17/6 hoặc x=1/6

c: =>\(\left|x-\dfrac{1}{3}\right|=\dfrac{5}{2}-\dfrac{1}{4}+\dfrac{2}{3}=\dfrac{35}{12}\)

=>x-1/3=35/12 hoặc x-1/3=-35/12

=>x=39/12=13/4 hoặc x=-31/12

d: =>|x-5/8|=3/4

=>x-5/8=3/4 hoặc x-5/8=-3/4

=>x=11/8 hoặc x=-1/8

4 tháng 8 2019

a) \(\frac{1}{4}+\frac{3}{4}x=\frac{3}{4}\Leftrightarrow\frac{3}{4}x=\frac{1}{2}\Leftrightarrow x=\frac{1}{2}\times\frac{4}{3}\Leftrightarrow x=\frac{2}{3}\)

b)\(1\frac{3}{4}x+1\frac{1}{2}=-\frac{4}{5}\Leftrightarrow\frac{7}{4}x+\frac{3}{2}=-\frac{4}{5}\Leftrightarrow\frac{7}{4}x=-\frac{23}{10}\)

\(\Leftrightarrow x=-\frac{23}{10}\times\frac{4}{7}\Leftrightarrow x=-\frac{46}{35}\)

c)\(\frac{3}{4}x+\frac{2}{5}x=1,2\Leftrightarrow x\left(\frac{3}{4}+\frac{2}{5}\right)=1,2\Leftrightarrow\frac{23}{20}x=1,2\)

\(\Leftrightarrow x=1,2\times\frac{20}{23}\Leftrightarrow x=\frac{24}{23}\)

d)\(\frac{3}{7}+\frac{1}{7}:x=\frac{3}{14}\Leftrightarrow\frac{1}{7x}=\frac{3}{14}-\frac{3}{7}\Leftrightarrow\frac{1}{7x}=-\frac{3}{14}\Leftrightarrow14=-3\times7x\)

\(\Leftrightarrow-21x=14\Leftrightarrow x=-\frac{2}{3}\)

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

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

\(\Leftrightarrow\left[{}\begin{matrix}x=\frac{11}{20}\\x=\frac{21}{20}\end{matrix}\right.\)

4 tháng 8 2019

a, \(\frac{1}{4}+\frac{3}{4}x=\frac{3}{4}\\ \Rightarrow\frac{3}{4}x=\frac{1}{2}\\ \Rightarrow x=\frac{2}{3}\)

Vậy \(x=\frac{2}{3}\)

b, \(1\frac{3}{4}x+1\frac{1}{2}=\frac{-4}{5}\\ \frac{7}{4}x+\frac{3}{2}=\frac{-4}{5}\\ \Rightarrow\frac{7}{4}x=\frac{-23}{10}\\ \Rightarrow x=\frac{-46}{35}\)

Vậy \(x=\frac{-46}{35}\)

c, \(\frac{3}{4}x+\frac{2}{5}x=1,2\\ x\left(\frac{3}{4}+\frac{2}{5}\right)=\frac{6}{5}\\ x\cdot\frac{23}{20}=\frac{6}{5}\\ \Rightarrow x=\frac{24}{23}\)

Vậy \(x=\frac{24}{23}\)

d, \(\frac{3}{7}+\frac{1}{7}:x=\frac{3}{14}\\ \Rightarrow\frac{1}{7}:x=\frac{-3}{14}\\ \Rightarrow x=\frac{-2}{3}\)

Vậy \(x=\frac{-2}{3}\)

e, \(\frac{-3}{4}-\left|\frac{4}{5}-x\right|=-1\\ \Rightarrow\left|\frac{4}{5}-x\right|=\frac{1}{4}\\ \Rightarrow\left[{}\begin{matrix}\frac{4}{5}-x=\frac{1}{4}\\\frac{4}{5}-x=\frac{-1}{4}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\frac{11}{20}\\x=\frac{21}{20}\end{matrix}\right.\)

Vậy \(x\in\left\{\frac{11}{20};\frac{21}{20}\right\}\)