SOLUTION
Given the question in the image, the following are steps to solve the problem.
Step 1: Write out the function that defines the cost of the condominium
[tex]\begin{gathered} f(x)=1200x+2400 \\ \text{where x }represents\text{ number of months} \end{gathered}[/tex]Step 2: Calculate how much Karen pays for the condominium after living there for 12 months by substituting 12 for x in the function defined above:
[tex]\begin{gathered} f(x)=1200x+2400 \\ x=12 \\ f(12)=1200(12)+2400 \\ f(12)=14400+2400 \\ f(12)=16,800 \end{gathered}[/tex]Hence, the amount Karen will pay after living there for 12 months will be $16,800 which is option D