Answer:
[tex]f(x) = \left(\frac{3}{2}\right)\cdot \left(\frac{8}{7} \right)^{-x}[/tex]
Step-by-step explanation:
An exponential decay function has the following form:
[tex]y = y_{o}\cdot b^{r\cdot t}[/tex], where [tex]r < 0[/tex] and [tex]y_{o} \in \mathbb{R^{+}}, y > 1[/tex]
By comparison, the function [tex]f(x) = \left(\frac{3}{2}\right)\cdot \left(\frac{8}{7} \right)^{-x}[/tex] is an exponential decay function.