To solve this problem we need to follow this steps:
• Step 1: Find the function
,• Step 2: Find how much he will pay
Step 1. Since each TV costs $1200, to find the cost to pay for "x" number of TVs, we will need to multiply 1200 by x. Then, since the shipping cost is $90, to the initial cost of the TVs, we add 90.
In summary, the function for "x" number of TVs will be as follows:
[tex]f(x)=1200x+90[/tex]Step 2. With the information from the last step, we calculate the cost for 3 TVs, which means x=3. We substitute that value into the funtion, and we get:
[tex]\begin{gathered} f(3)=1200(3)+90 \\ f(3)=3600+90 \\ f(3)=3690 \end{gathered}[/tex]