It should be eight if I remember correctly
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:

Let the figure number be x.
Then the equation will be:
3x
There will be 3x circles in the figure number x.
So, number of circles in 50th figure will be
= 3(50)
= 3 × 50
= 150 circles
Answer:
18(x - 3)
Step-by-step explanation:
18x - 54 ← factor out 18 from each term
= 18(x - 3)