2)
\(\left|3,5-x\right|+\frac{2}{7}=\frac{16}{7}\)
\(\Rightarrow\left|3,5-x\right|=\frac{16}{7}-\frac{2}{7}\)
\(\Rightarrow\left|3,5-x\right|=2\)
\(\Rightarrow\left[{}\begin{matrix}3,5-x=2\\3,5-x=-2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=3,5-2\\x=3,5+2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1,5\\x=5,5\end{matrix}\right.\)
Vậy \(x\in\left\{1,5;5,5\right\}.\)
Chúc bạn học tốt!