2.5-X=1.3 suy ra X =1.2
2-5-X=-1.3 suy ra X=3.8
de vay ma ko bít
\(\left|2,5-x\right|=1,3\)
\(\Leftrightarrow\orbr{\begin{cases}2,5-x=1,3\\2,5-x=-1,3\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=2,5-1,3\\x=2,5+1,3\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=1,2\\x=3,8\end{cases}}\)
Vậy \(x\in\){1,2 ; 3,8}
\(\Rightarrow2,5-x=1,3\) \(hoặc-1,3\)
\(2,5-x=1,3\Rightarrow x=1,2\)
\(2,5-x=-1,3\Rightarrow x=3,8\)