\(\left|2x-5\right|=7-4=3\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-5=3\\2x-5=-3\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-1\end{matrix}\right.\)
Ta có: \(\left|2x-5\right|+4=7\)
\(\Leftrightarrow\left|2x-5\right|=3\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-5=3\\2x-5=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=8\\2x=2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=1\end{matrix}\right.\)
| 2x - 5 | + 4 = 7
| 2x - 5 | = 7 - 4
| 2x - 5 | = 3
TH1: 2x - 5 = 3 TH2: 2x - 5 = -3
=> 2x = 8 => 2x = 2
=> x = 4 => x = 1
Vậy x= 4 hoặc x= 1