For this case we have:
Cost of manufactures of T-shirts 
where x represents the number of T-shirts
Part A:
Substituting
in the total cost equation you have to:

Thus, the cost of 8 shirts will be 
Part B:
If
then

Thus, the cost of 12 shirts will be 
Answer:

<span>Remember, the domain of a function is all of the x values in
the (x,y) coordinates. For this, let’s take a few bench mark coordinates. (0,0)
(1,2.5)(2,0) (3, -9). Those definitely aren’t all real numbers, so eliminate A.
X is not only less than or equal to 0, so eliminate C. </span>
<span>It’s B.</span>
Answer: 18 meters/s
Step-by-step explanation: Divide meters by seconds to find out how many meters the horse traveled per second.