a: \(\dfrac{3}{4}-\left|x-\dfrac{3}{2}\right|=\dfrac{1}{6}\)
=>\(\left|x-\dfrac{3}{2}\right|=\dfrac{3}{4}-\dfrac{1}{6}=\dfrac{7}{12}\)
=>\(\left[{}\begin{matrix}x-\dfrac{3}{2}=\dfrac{7}{12}\\x-\dfrac{3}{2}=-\dfrac{7}{12}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}+\dfrac{7}{12}=\dfrac{25}{12}\\x=\dfrac{3}{2}-\dfrac{7}{12}=\dfrac{11}{12}\end{matrix}\right.\)
b: \(\left(\dfrac{1}{3}-\dfrac{3}{2}x\right)^2=\dfrac{9}{4}\)
=>\(\left[{}\begin{matrix}\dfrac{1}{3}-\dfrac{3}{2}x=\dfrac{3}{2}\\\dfrac{1}{3}-\dfrac{3}{2}x=-\dfrac{3}{2}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\dfrac{3}{2}x=\dfrac{1}{3}-\dfrac{3}{2}=-\dfrac{7}{6}\\\dfrac{3}{2}x=\dfrac{1}{3}+\dfrac{3}{2}=\dfrac{11}{6}\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=-\dfrac{7}{6}:\dfrac{3}{2}=-\dfrac{7}{6}\cdot\dfrac{2}{3}=-\dfrac{7}{9}\\x=\dfrac{11}{6}:\dfrac{3}{2}=\dfrac{11}{6}\cdot\dfrac{2}{3}=\dfrac{11}{9}\end{matrix}\right.\)