\(\left(\frac{9}{14}\right)^2.\left(\frac{-7}{3}\right)^3=\left(\frac{9}{14}\right)^2.\left(\frac{-7}{3}\right)^2.\left(-\frac{7}{3}\right)\)
\(=\left(\frac{9}{14}.\frac{\left(-7\right)}{3}\right)^2.\left(-\frac{7}{3}\right)\)
\(=\left(\frac{3}{2}\right)^2.\left(-\frac{7}{3}\right)\)
\(=\frac{9}{4}.\frac{-7}{3}=-\frac{63}{12}\)