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29 tháng 10 2017

\(\left|x-\dfrac{1}{3}\right|+\dfrac{4}{5}=\left|\left(-3,2\right)+\dfrac{2}{5}\right|\)

\(\Leftrightarrow\left|x-\dfrac{1}{3}\right|+\dfrac{4}{5}=\dfrac{14}{5}\)

\(\Rightarrow\left|x-\dfrac{1}{3}\right|=\dfrac{14}{5}-\dfrac{4}{5}\)

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

\(\Rightarrow\left[{}\begin{matrix}x-\dfrac{1}{3}=2\\x-\dfrac{1}{3}=-2\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{3}\\x=\dfrac{-5}{3}\end{matrix}\right.\)

Vậy..............

29 tháng 10 2017

\(\left | x - \frac{1}{3} \right | + \frac{4}{5} = \left | \left ( - 3,2 \right ) + \frac{2}{5}\right |\)

\(\left | x - \frac{1}{3} \right | + \frac{4}{5} = \left | - \frac{14}{5} \right |\)

\(\left | x - \frac{1}{3} \right | + \frac{4}{5} = \frac{14}{5} \)

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

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

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

\(x = \frac{7}{3}\)

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

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

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

Vậy x = \(x = \frac{7}{3}; x = - \frac{5}{3}\)

9 tháng 6 2017

\(\left\{\dfrac{-5< 0< -0,4}{x\in Z}\right\}\Rightarrow x\in\left\{-4;-3;-2;-1\right\}\)

31 tháng 8 2017

chiu thôi khocroikhocroikhocroileo nheo qua

11 tháng 2 2018

a) \(\left|x-\frac{1}{3}\right|+\frac{4}{5}=\left|\left(-3,2\right)+\frac{2}{5}\right|\)

\(\left|x-\frac{1}{3}\right|+\frac{4}{5}=\left|\frac{-16}{5}+\frac{2}{5}\right|\)

\(\left|x-\frac{1}{3}\right|+\frac{4}{5}=\left|\frac{-14}{5}\right|\)

\(\left|x-\frac{1}{3}\right|+\frac{4}{5}=\frac{14}{5}\)

\(\left|x-\frac{1}{3}\right|=\frac{14}{5}-\frac{4}{5}\)

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

\(\Rightarrow\orbr{\begin{cases}x-\frac{1}{3}=2\\x-\frac{1}{3}=-2\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{7}{3}\\x=\frac{-5}{3}\end{cases}}\)

11 tháng 2 2018

làm tiếp câu a) nhé

b) \(\left(x-7\right)^{x+1}-\left(x-7\right)^{x+11}=0\)

\(\left(x-7\right)^{x+1}.\left[1-\left(x-7\right)^{10}\right]=0\)

\(\Rightarrow\orbr{\begin{cases}\left(x-7\right)^{x+1}=0\\1-\left(x-7\right)^{10}=0\end{cases}}\Rightarrow\orbr{\begin{cases}x-7=0\\\left(x-7\right)^{10}=1\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=7\\x-7=1\end{cases}}\Rightarrow\orbr{\begin{cases}x=7\\x=8\end{cases}}\)

\(\left|x-\dfrac{1}{3}\right|+\dfrac{4}{5}=\left|-3,2+\dfrac{2}{5}\right|\)

=>\(\left|x-\dfrac{1}{3}\right|+0,8=\left|-3,2+0,4\right|=2,8\)

=>\(\left|x-\dfrac{1}{3}\right|=2,8-0,8=2\)

=>\(\left[{}\begin{matrix}x-\dfrac{1}{3}=2\\x-\dfrac{1}{3}=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{3}\\x=-\dfrac{5}{3}\end{matrix}\right.\)

2 tháng 9 2017

a, \(\left|x+1,2\right|=0,5\)

\(\Leftrightarrow\left[{}\begin{matrix}x+1,2=0,5\\x+1,2=-0,5\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-0,7\\x=-1,7\end{matrix}\right.\)

Vậy ....

b, \(\left|x-\dfrac{1}{2}\right|+\dfrac{5}{6}=1\dfrac{1}{2}\)

\(\Leftrightarrow\left|x-\dfrac{1}{2}\right|=1\dfrac{1}{2}-\dfrac{5}{6}\)

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

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

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{7}{6}\\x=\dfrac{-1}{6}\end{matrix}\right.\)

Vậy .....

c, \(\left|x-\dfrac{1}{2}\right|+\dfrac{4}{5}=\left|-3,2+\dfrac{2}{5}\right|\)

\(\left|x-\dfrac{1}{2}\right|+\dfrac{4}{5}=\left|-2,8\right|\)

\(\left|x-\dfrac{1}{2}\right|+\dfrac{4}{5}=2,8\)

\(\left|x-\dfrac{1}{2}\right|=2,8-\dfrac{4}{5}\)

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

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

\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5}{2}\\x=\dfrac{-8}{5}\end{matrix}\right.\)

Vậy ...

2 tháng 9 2017

bn giúp mk hai bài toán trước nữa đi. Cảm ơn nha!

22 tháng 2 2018

Ta có: \(\left|x-\dfrac{1}{3}\right|\)+0,8 = \(\left|-3,2+0,4\right|\)

---> \(\left|x-\dfrac{1}{3}\right|\)+0,8 =2,8 ---> \(\left|x-\dfrac{1}{3}\right|\)= 2,8-0,8=2 --> TH1: x-\(\dfrac{1}{3}\) = 2 --> x= 2+ \(\dfrac{1}{3}\)= \(\dfrac{7}{3}\) TH2: x-\(\dfrac{1}{3}\) = -2---> x= -2+\(\dfrac{1}{3}\)=\(\dfrac{-5}{3}\) Vạy x =\(\dfrac{-5}{3}\) hoặc x= \(\dfrac{7}{3}\) Tick cho mik nha!!

a) \(\left|x-\dfrac{1}{3}\right|+\dfrac{4}{5}=\left|\left(-3,2\right)+\dfrac{2}{5}\right|\)

\(\Rightarrow\left|x-\dfrac{1}{3}\right|+0,8=\left|-3,2+0,4\right|\)

\(\Rightarrow\left|x-\dfrac{1}{3}\right|+0,8=2,8\)

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

\(\Rightarrow\left[{}\begin{matrix}x-\dfrac{1}{3}=2\\x-\dfrac{1}{3}=-2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{3}\\x=\dfrac{-5}{3}\end{matrix}\right.\)