Answer:
![Y = 12,000 \cdot (2)^X](https://img.qammunity.org/2019/formulas/mathematics/middle-school/qcgr8xcig113liq01v3mupehdc5tt5ruhr.png)
Explanation:
The exponential function is given by:
![y =a \cdot b^x](https://img.qammunity.org/2019/formulas/mathematics/middle-school/dk051i4x92l01myb8kk0sqr8e8cbm58dn2.png)
where,
a is the initial values and b is the growth factor.
As per the statement:
The initial number of bacteria in a culture is 12,000.
⇒Number of bacteria initially(a) = 12,000
It is also given that the culture doubles each day.
⇒ growth factor
![b= 2](https://img.qammunity.org/2019/formulas/mathematics/middle-school/5emncz6fbctupuk2hs3bo1yjeq8ftiyfb0.png)
We have to find the exponential function to model the population Y of bacteria after X days.
By definition of exponential function:
![Y = 12,000 \cdot (2)^X](https://img.qammunity.org/2019/formulas/mathematics/middle-school/qcgr8xcig113liq01v3mupehdc5tt5ruhr.png)
where, x represents the days and Y is the population after X days.
Therefore, an exponential function to model the population is,
![Y = 12,000 \cdot (2)^X](https://img.qammunity.org/2019/formulas/mathematics/middle-school/qcgr8xcig113liq01v3mupehdc5tt5ruhr.png)