Answer
Japan and Russia.
Work Step by Step
The mathematical model for exponential growth or decay is given by
$ f(t)= A_{0}e^{kt}$ or $ A= A_{0}e^{kt}$.
If $ k \gt 0$, the function models the amount of a growing entity.
$ A_{0}$ is the original amount, or size, of the growing entity at time t = 0,
$ A $ is the amount at time $ t $, and
$ k $ is a constant representing the growth rate.
If k $ \lt $ 0, the function models the amount of a decaying entity
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We see that countries with negative k are Japan and Russia.
