Given:
Initial number of foxes = 5
Each year there were four times as many foxes as the year before.
Let's find the number of foxes after X years.
Here, we are to apply the exponential growth function:
[tex]f(x)=a(b)^x[/tex]Where:
a is the initial number of foxes = 5
b is the growth factor.
Since each year there were four times as many foxes as the year before, the growth factor will be:
b = 4
Therefore, the number of foxes after x years will be:
[tex]f(x)=5(4)^x[/tex]Where x represents the number if years.
ANSWER:
[tex]f(x)=5(4)^x[/tex]