\(\Leftrightarrow3\cdot\left|2x-5\right|=12\)
\(\Leftrightarrow\left|2x-5\right|=4\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-5=4\\2x-5=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\\x=\dfrac{1}{2}\end{matrix}\right.\)
\(\Rightarrow3\left|5-2x\right|=12\\ \Rightarrow\left|5-2x\right|=4\Rightarrow\left[{}\begin{matrix}5-2x=4\\2x-5=4\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{2}\\x=\dfrac{9}{2}\end{matrix}\right.\)