Chapter 4 - Section 4.1 - Exponential Functions - 4.1 Exercises - Page 337: 54

a) $N(t)=320⋅2^t$ b) $N(8)=81,920$ mice

a) The base form of exponential functions is $f(x)=n⋅b^x$, where $n$ is the initial number and $b$ is the growth factor. In this exercise, there are initially $320$ mice, so that corresponds to $n$. And the growth factor is $2$, so that corresponds to $b$. Thus, the equation: $N(t)=320⋅2^t$ b) $N(8)=320\cdot 2^8=$ $320\cdot 256=81,920$ mice