\(\Rightarrow\left[\begin{array}{nghiempt}\frac{2}{5}< x-\frac{7}{5}< \frac{3}{5}\\\frac{2}{5}< -\left(x-\frac{7}{5}\right)< \frac{3}{5}\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}\frac{2}{5}+\frac{7}{5}< x-\frac{7}{5}+\frac{7}{5}< \frac{3}{5}+\frac{7}{5}\\\frac{2}{5}< \frac{7}{5}-x< \frac{3}{5}\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}\frac{9}{5}< x< 2\\\frac{2}{5}-\frac{7}{5}< \frac{7}{5}-x-\frac{7}{5}< \frac{3}{5}-\frac{7}{5}\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}\frac{9}{5}< x< 2\\-1< -x< -\frac{4}{5}\end{array}\right.\)
\(\Rightarrow\left[\begin{array}{nghiempt}\frac{9}{5}< x< 2\\1>x>\frac{4}{5}\end{array}\right.\)
\(\frac{2}{5}< \left|x-\frac{7}{5}\right|< \frac{3}{5}\)
\(\Rightarrow\frac{4}{10}< \left|x-\frac{7}{5}\right|< \frac{6}{10}\)
\(\Rightarrow\left|x-\frac{7}{5}\right|=1\)
\(\Rightarrow x-\frac{7}{5}=1;x-\frac{7}{5}=-1\)
\(\Rightarrow x=1+\frac{7}{5};x=-1+\frac{7}{5}\)
\(\Rightarrow x=\frac{12}{5};\frac{2}{5}\)
