\(\left|2x+1\right|-\left|5x-2\right|=3\\ \Leftrightarrow\left|2x+1\right|-\left|5x-2\right|-3=0\\ \Leftrightarrow\left[{}\begin{matrix}2x+1=5x-2-3\\2x+1=-5x+2-3\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}2x-5x=-2-1-3\\2x+5x=-3-1+2\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}-3x=-6\\7x=-2\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=-\dfrac{2}{7}\end{matrix}\right.\)
\(\left|3x-1\right|=\left|5x+2\right|\\ \Leftrightarrow\left[{}\begin{matrix}3x-1=5x+2\\3x-1=-5x-2\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}3x-5x=2+1\\3x+5x=-2+1\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}-2x=3\\8x=-1\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{3}{2}\\x=-\dfrac{1}{8}\end{matrix}\right.\)
