QuestionDetermine the rule of the exponential function in the form $y=a c^{x}$ that is represented in the table of values below. \begin{tabular}{|c|c|} \hline$x$ & $y$ \\ \hline-1 & $\frac{8}{15}$ \\ \hline 0 & $\frac{2}{5}$ \\ \hline 1 & $\frac{3}{10}$ \\ \hline \end{tabular}