\(\left|3x-2\right|=0\\ \Leftrightarrow3x-2=0\\ \Leftrightarrow3x=2\\ \Leftrightarrow x=\dfrac{2}{3}\\ ---\\ \left|3x-2\right|=4\\ \Leftrightarrow\left[{}\begin{matrix}3x-2=4\\-\left(3x-2\right)=4\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}3x=6\\-3x=2\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=-\dfrac{2}{3}\end{matrix}\right.\)
\(\sqrt{3x+1}=\dfrac{2}{3}\left(ĐKXĐ:3x+1\ge0\Leftrightarrow x\ge-\dfrac{1}{3}\right)\\ \Leftrightarrow\left|3x+1\right|=\left(\dfrac{2}{3}\right)^2=\dfrac{4}{9}\\ \Leftrightarrow\left[{}\begin{matrix}3x+1=\dfrac{4}{9}\\-3x-1=\dfrac{4}{9}\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}3x=-\dfrac{5}{9}\\-3x=\dfrac{13}{9}\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{5}{9}:3=-\dfrac{5}{27}\left(nhận\right)\\x=\dfrac{13}{9}:\left(-3\right)=\dfrac{-13}{27}\left(loại\right)\end{matrix}\right.\\ Vậy:x=-\dfrac{5}{27}\)
