For this case we have a function of the form:
y = A * (b) ^ x
Where,
A: initial amount
b: growth rate
x: domain of the function.
We have then that the function is:
y = 2 * (3) ^ x
For example,
for x = 0:
y = 2 * (3) ^ 0
y = 2
for x = 1:
y = 2 * (3) ^ 1
y = 6
for x = 2:
y = 2 * (3) ^ 2
y = 18
for x = 3:
y = 2 * (3) ^ 3
y = 54
Answer:
y = 2 * (3) ^ x