\(a,\left|5x-\dfrac{1}{6}\right|-2x=12\)
\(\Leftrightarrow\left|5x-\dfrac{1}{6}\right|=12+2x\)
\(\Leftrightarrow\left[{}\begin{matrix}5x-\dfrac{1}{6}=12+2x\\5x-\dfrac{1}{6}=-\left(12+2x\right)\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}5x-\dfrac{1}{6}=12+2x\\5x-\dfrac{1}{6}=-12-2x\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}3x=\dfrac{73}{6}\\7x=-\dfrac{71}{6}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{73}{18}\\x=-\dfrac{71}{42}\end{matrix}\right.\)
\(b,\left|7x-\dfrac{4}{3}\right|-\dfrac{3}{2}x=7\)
\(\Leftrightarrow\left|7x-\dfrac{4}{3}\right|=7+\dfrac{3}{2}x\)
\(\Leftrightarrow\left[{}\begin{matrix}7x-\dfrac{4}{3}=7+\dfrac{3}{2}x\\7x-\dfrac{4}{3}=-7-\dfrac{3}{2}x\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{11}{2}x=\dfrac{25}{3}\\\dfrac{17}{2}x=-\dfrac{17}{3}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{50}{33}\\x=-\dfrac{2}{3}\end{matrix}\right.\)
