Câu 1:
\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{3}=\dfrac{2}{3}\\x+\dfrac{1}{3}=-\dfrac{2}{3}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=-1\end{matrix}\right.\)
\(1,\Leftrightarrow\left(x+\dfrac{1}{3}\right)^2=\dfrac{4}{9}\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{3}=\dfrac{2}{3}\\x+\dfrac{1}{3}=-\dfrac{2}{3}\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=-1\end{matrix}\right.\\ 2,=15:\left(\dfrac{2}{3}\right)^4\cdot\left(\dfrac{2}{3}\right)^6:\left(\dfrac{2}{3}\right)^9=15\cdot\left(\dfrac{2}{3}\right)^{-7}=15\cdot\dfrac{3^7}{2^7}=15\cdot\dfrac{2187}{128}=\dfrac{32805}{128}\)