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:

Answer:
How do we get a bigger number? Subtracting or dividing will just make it smaller. So we have to multiply. We need it about 4 times bigger (3 x 28 = 84, 4 x 28 .
Step-by-step explanation:
The answer is B because Chris and three of his friends is 4. Then, each person paid $9 so 4 x 3 = x.