Bài 2:
\(a,\Leftrightarrow\dfrac{7}{9}x=\dfrac{20}{9}\Leftrightarrow x=\dfrac{20}{7}\\ b,\Leftrightarrow\dfrac{12}{13}x=-\dfrac{1}{3}-\dfrac{6}{13}=-\dfrac{31}{39}\\ \Leftrightarrow x=-\dfrac{31}{36}\\ c,\Leftrightarrow\left|3x-\dfrac{2}{5}\right|=\dfrac{3}{4}\Leftrightarrow\left[{}\begin{matrix}3x=\dfrac{23}{20}\\3x=-\dfrac{7}{20}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{23}{60}\\x=-\dfrac{7}{60}\end{matrix}\right.\)