a)\(\left(x-2\right)\left(x+\dfrac{2}{3}\right)>0\)
\(\Rightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x-2>0\\x+\dfrac{2}{3}>0\end{matrix}\right.\\\left\{{}\begin{matrix}x-2< 0\\x+\dfrac{2}{3}< 0\end{matrix}\right.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x>2\\x>-\dfrac{2}{3}\end{matrix}\right.\\\left\{{}\begin{matrix}x< 2\\x< -\dfrac{2}{3}\end{matrix}\right.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x>2\\x< -\dfrac{2}{3}\end{matrix}\right.\)
b) \(\dfrac{x}{\dfrac{9}{14}}=\dfrac{7}{\dfrac{3}{x}}\Leftrightarrow x^2=\dfrac{7}{3}.\dfrac{9}{14}=\dfrac{3}{2}\)
\(\Rightarrow\left[{}\begin{matrix}x=\sqrt{\dfrac{3}{2}}\\x=-\sqrt{\dfrac{3}{2}}\end{matrix}\right.\)
