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28 tháng 3 2017

e cảm ơn chị ạ!

28 tháng 3 2017

You chép mạng à?

26 tháng 6 2017

Em không hiểu anh viết gì hết.lolanglolanglolang

26 tháng 6 2017

khỏi hỉu

19 tháng 4 2019

Câu a \(\left|2x-\frac{1}{3}\right|+\frac{5}{6}=1\)

19 tháng 4 2019

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

\(\Leftrightarrow\orbr{\begin{cases}x+\frac{1}{2}=0\\\frac{2}{3}-2x=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{-1}{2}\\x=\frac{1}{3}\end{cases}}\)

Vây \(x\in\left\{\frac{-1}{2};\frac{1}{3}\right\}\)

7 tháng 8 2019

a)x-5=7

=> x=9

b)2.x+6=24

=>2x=18

=>x=9

Tìm x :

a) \(x-5=49:7\)

\(\Leftrightarrow x-5=7\)

\(\Leftrightarrow x=7+5\)

\(\Leftrightarrow x=12\)

Vậy : \(x=12\)

b) \(2x+6=24\)

\(\Leftrightarrow2x=24-6=18\)

\(\Leftrightarrow x=18:2\)

\(\Leftrightarrow x=9\)

Vậy : \(x=9\)

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

\(\Leftrightarrow\frac{1}{3}:x=5-\frac{1}{2}=\frac{9}{5}\)

\(\Leftrightarrow x=\frac{1}{3}:\frac{9}{5}\)

\(\Leftrightarrow x=\frac{5}{27}\)

Vậy : \(x=\frac{5}{27}\)

d) \(\frac{1}{6}.x-\frac{1}{3}=2\)

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

\(\Leftrightarrow x=\frac{5}{3}:\frac{1}{6}\)

\(\Leftrightarrow x=10\)

Vậy : \(x=10\)

e) \(\frac{x}{27}=\frac{3}{x}\)

\(\Leftrightarrow x.x=27.3\)

\(\Leftrightarrow x^2=81\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-9\\x=9\end{matrix}\right.\)\(x\in N\)

\(\Rightarrow x=9\)

Vậy : \(x=9\)

g) \(1200:24-\left(17-x\right)=36\)

\(\Leftrightarrow50-17+x=36\)

\(\Leftrightarrow33+x=36\)

\(\Leftrightarrow x=36-33\)

\(\Leftrightarrow x=3\)

Vậy : \(x=3\)

h) \(674-\left(12+x\right)=427\)

\(\Leftrightarrow12+x=674-427=247\)

\(\Leftrightarrow x=247-12\)

\(\Leftrightarrow x=230\)

Vậy : \(x=230\)

k) \(36.\left(x-9\right)=900\)

\(\Leftrightarrow x-9=900:36\)

\(\Leftrightarrow x-9=25\)

\(\Leftrightarrow x=25+9\)

\(\Leftrightarrow x=34\)

m) \(1,2:x+3,8:x=2,5\)

\(\Leftrightarrow\left(1,2-3,8\right):x=2,5\)

\(\Leftrightarrow-2,6:x=2,5\)

\(\Leftrightarrow x=\frac{-2,6}{2,5}=-\frac{26}{25}\)

Vậy : \(x=-\frac{26}{25}\)

n) \(\left(\frac{1}{2.4}+\frac{1}{4.6}+\frac{1}{6.8}+\frac{1}{8.10}\right).x=\frac{1}{3}\)

\(\Leftrightarrow\frac{1}{2}.\left(\frac{2}{2.4}+\frac{2}{4.6}+\frac{2}{6.8}+\frac{2}{8.10}\right).x=\frac{1}{3}\)

\(\Leftrightarrow\left[\frac{1}{2}.\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+\frac{1}{6}-\frac{1}{8}+\frac{1}{8}-\frac{1}{10}\right)\right].x=\frac{1}{3}\)

\(\Leftrightarrow\left[\frac{1}{2}.\left(1-\frac{1}{10}\right)\right].x=\frac{1}{3}\)

\(\Leftrightarrow\frac{1}{2}.\frac{9}{10}.x=\frac{1}{3}\)

\(\Leftrightarrow\frac{9}{20}.x=\frac{1}{3}\)

\(\Leftrightarrow x=\frac{1}{3}:\frac{9}{20}\)

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

Vậy : \(x=\frac{20}{27}\)

5 tháng 7 2018

a) \(\left(5x+1\right)^2=\frac{36}{49}\)

\(\Rightarrow\left(5x+1\right)^2=\left(\frac{6}{7}\right)^2=\left(\frac{-6}{7}\right)^2\)

\(\Rightarrow\hept{\begin{cases}5x+1=\frac{6}{7}\\5x+1=\frac{-6}{7}\end{cases}}\Rightarrow\hept{\begin{cases}5x=\frac{-1}{7}\\5x=\frac{-13}{7}\end{cases}\Rightarrow\hept{\begin{cases}x=\frac{-1}{35}\\x=\frac{-13}{35}\end{cases}}}\)

b) \(\left(x-\frac{2}{9}\right)^3=\left(\frac{2}{3}\right)^6\)

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

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

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

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

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

5 tháng 7 2018

\(a.\left(5x+1\right)^2=\frac{36}{49}\)

\(\left(5x+1\right)^2=\frac{6^2}{7^2}\)

\(\left(5x+1\right)^2=\left(\frac{6}{7}\right)^2\)

\(\Rightarrow5x+1=\frac{6}{7}\)

\(\Rightarrow5x=\frac{6}{7}-1\)

\(\Rightarrow5x=-\frac{1}{7}\)

\(\Rightarrow x=-\frac{1}{7}:5\)

\(\Rightarrow x=-\frac{1}{35}\)

Vậy \(x=-\frac{1}{35}\)

\(b\left(x-\frac{2}{9}\right)^3=\left(\frac{2}{3}\right).^6\)

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

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

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

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

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

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

Vậy \(x=\frac{2}{3}\)