Answer:
.
Explanation:
Year 0 = 4 fishes
Since we are given that Each year, there were three times as many fish as the year before.
So , Year 1 =
dishes
Year 2 =
fishes
And so on
So, we can use formula of exponential growth :

where y is the number of fishes after x years
a is the initial amount
b is the growth factor
x is the number of years
a = 4
b = 3
Substitute the values in the formula :

To Check substitute x = 0


Park rangers released 4 fish into the pond in year 0
To Check substitute x = 1


Park rangers released 12 fish into the pond in year 1
Hence verified
Hence a function to represent this senario is
.