\(a,\left|2,5-x\right|=1,3\)
\(\Rightarrow2,5-x=\left\{{}\begin{matrix}-1,3\\1,3\end{matrix}\right.\)
\(TH1:2,5-x=1,3\)
\(x=2,5-1,3\)
\(x=1,2\)
\(TH2:2,5-x=-1,3\)
\(x=2,5-\left(-1,3\right)\)
\(x=3,8\)
Vậy \(x=\left\{{}\begin{matrix}1,2\\3,8\end{matrix}\right.\)
\(b,1,6-\left|x-0,2\right|=0\)
\(\left|x-0,2\right|=1,6-0=1,6\)
\(\Rightarrow x-0,2\) \(=\left\{{}\begin{matrix}-1,6\\1,6\end{matrix}\right.\)
\(TH1:x-0,2=-1,6\)
\(x=-1,6+0,2\)
\(x=-1,4\)
\(TH2:x-0,2=1,6\)
\(x=1,6+0,2\)
\(x=1,8\)
Vậy \(x\) \(=\left\{{}\begin{matrix}-1,4\\1,8\end{matrix}\right.\)