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10 tháng 10 2017

a)\(6:\left(\frac{\frac{3}{5}x+3}{20}+9\right)=\frac{3}{5}\)

\(\frac{\frac{3}{5}x+3}{20}+9=6:\frac{3}{5}\)

\(\frac{\frac{3}{5}x+3}{20}+9=6.\frac{5}{3}\)

\(\frac{\frac{3}{5}x+3}{20}+9=10\)

\(\frac{\frac{3}{5}x+3}{20}=10-9\)

\(\left(\frac{3}{5}x+3\right):20=1\)

\(\frac{3}{5}x+3=1.20\)

\(\frac{3}{5}x+3=20\)

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

\(\frac{3}{5}x=17\)

\(x=17:\frac{3}{5}\)

\(x=17.\frac{5}{3}\)

\(x=\frac{85}{3}\)

b)l x+3 l = l -9 l

 l x+3l=9

\(\orbr{\begin{cases}x+3=9\\x+3=-9\end{cases}\Rightarrow\orbr{\begin{cases}x=9-3\\x=-9-3\end{cases}\Rightarrow}\orbr{\begin{cases}x=6\\x=-12\end{cases}}}\)

19 tháng 10 2017

a, x=85/3

b, x=6 hoặc x=-12

24 tháng 7 2018

Bạn đăng ít một thôi!

24 tháng 7 2018

mk lỡ đăng rồi bạn ạ 

8 tháng 2 2019

\(a)\frac{8}{9}x-\frac{2}{3}=\frac{1}{3}x+1\frac{1}{3}\)

\(\Rightarrow\frac{8}{9}x-\frac{1}{3}x=\frac{2}{3}+1\frac{1}{3}\)

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

\(\Rightarrow\frac{5}{9}x=2\Rightarrow x=2\div\frac{5}{9}=\frac{18}{5}\)

8 tháng 2 2019

\(b)(\frac{-2}{5}+\frac{3}{7})-(\frac{4}{9}+\frac{12}{20}-\frac{13}{25})+\frac{7}{35}\)

\(=\frac{1}{35}-(\frac{4}{9}+\frac{3}{5}-\frac{13}{25})+\frac{1}{5}\)

\(=\frac{1}{35}-(\frac{4}{9}+\frac{15}{25}-\frac{13}{25})+\frac{1}{5}\)

\(=\frac{1}{35}-(\frac{4}{9}+\frac{2}{25})+\frac{1}{5}\)

\(=\frac{1}{35}-\frac{118}{25}+\frac{1}{5}\)

Làm nốt

\(\left(2x+\frac{3}{5}\right)^2-\frac{9}{25}=0\)

\(\Leftrightarrow\left(2x+\frac{3}{5}\right)^2=\frac{9}{25}\)

\(\Leftrightarrow\left(2x+\frac{3}{5}\right)^2=\left(\frac{3}{5}\right)^2\)

\(\Leftrightarrow\orbr{\begin{cases}2x+\frac{3}{5}=\frac{3}{5}\\2x+\frac{3}{5}=-\frac{3}{5}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}2x=0\\2x=-\frac{6}{5}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=-\frac{3}{5}\end{cases}}\)

_Tần vũ_

\(3\left(3x-\frac{1}{2}\right)^3+\frac{1}{9}=0\)

\(\Leftrightarrow3\left(3x-\frac{1}{2}\right)^3=-\frac{1}{9}\)

\(\Leftrightarrow\left(3x-\frac{1}{2}\right)^3=-\frac{1}{27}\)

\(\Leftrightarrow\left(3x-\frac{1}{2}\right)^3=\left(-\frac{1}{3}\right)^3\)

\(\Leftrightarrow3x-\frac{1}{2}=\frac{-1}{3}\)

\(\Leftrightarrow3x=\frac{1}{6}\)

\(\Leftrightarrow x=\frac{1}{18}\)

_Tần Vũ_

21 tháng 4 2017

\(\Leftrightarrow\)\(x-\left(\frac{13x}{18}-\frac{4}{18}\right)=\frac{4}{9}\)

\(\Leftrightarrow\)\(\frac{18x}{18}-\frac{13x}{18}+\frac{4}{18}=\frac{4}{9}\)

\(\Leftrightarrow\)\(\frac{5x}{18}=\frac{4}{9}-\frac{4}{18}\)

\(\Leftrightarrow\)\(\frac{5x}{18}=\frac{2}{9}\)

\(\Leftrightarrow\)\(5x=\frac{18.2}{9}\)

\(\Leftrightarrow\)\(5x=4\)

\(\Leftrightarrow\)\(x=\frac{4}{5}\)

24 tháng 1 2020

a) \(\left(x+1\right)-\frac{x+1}{3}=\frac{5\left(x+1\right)-1}{6}\)

\(\Leftrightarrow6\left(x+1\right)-2\left(x+1\right)=5\left(x+1\right)-1\)

\(\Leftrightarrow6x+6-2x-2=5x+5-1\)

\(\Leftrightarrow6x-2x-5x=5-1-6+2\)

\(\Leftrightarrow-x=0\)

\(\Leftrightarrow x=0\)

b) \(\left(1-x\right)^2+\left(x+2\right)^2=2x\left(x-3\right)-7\)

\(\Leftrightarrow1-2x+x^2+x^2+4x+4=2x^2-6x-7\)

\(\Leftrightarrow2x^2+2x+5=2x^2-6x-7\)

\(\Leftrightarrow2x+6x=-7-5\)

\(\Leftrightarrow8x=-12\)

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

c) \(2+\frac{x-2}{2}-\frac{2x-4}{3}-\frac{5}{6}\left(2-x\right)=0\)

\(\Leftrightarrow2+\frac{x}{2}-1-\frac{2}{3}x+\frac{4}{3}-\frac{5}{3}+\frac{5}{6}x=0\)

\(\Leftrightarrow\frac{x}{2}-\frac{2}{3}x+\frac{5}{6}x=-2+1-\frac{4}{3}+\frac{5}{3}\)

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

\(\Leftrightarrow x=-1\)