Answer:
growth factor is 6
Explanation:

For any equation f(x)=ab^x
'a' is the initial value
b is the growth or decay factor .
When the value of b is greater than 1 then its growth factor
when the value of b is between 0 and 1 then it is decay factor
x is the number of years
In our given function

the value of b is 6
so growth factor is 6