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:

D is the correct answer.
We do not need math in this instance, just knowledge.
We know that the answer will point to 0, not infinity. There are constraints. Also note that 1.75*7=12.25, which means you can fit no more than 7 books in the bag.
What best describes this? Answer Choice D
The Vertical Angles Theorem states that if two angles are vertical angles, then they are congruent .Given <A and <B are vertical angles so they are equal.
<A=<B.
Measure of <A=x and <B=5x-80
Or 5x-80=x
Adding 80 both sides
5x-80+80=x+80
5x=x+80
Subtracting x both sides
5x-x=x-x+80
4x=80
Dividing both sides by 4
x=20
Measure of <A= x= 20 degrees.
Remark
It looks like all you want is question 6. If that is the case, there are two ways to do it.
Algebra
<u>First answer</u>
abs(b - 22) = 5 Equate to + 5
b - 22 = 5 Add 22 to both sides.
b = 5 + 22
b = 27
<u>Second Answer</u>
Equate to - 5
b - 22 = -5
b = 22 - 5
b = 17
Method Two
<u>Graph the question</u>
The graph y = abs(b - 22) is shown below in red.
The values of y when y =5 are shown in blue.
<span>A 15° sector in a circle has an area of 11.9 m2. What is the area of the circle?
The area of the circle will be found as follows:
the fraction of the sector=15/360=1/24
the area of the circle will be:
area=(fraction of the circle)/(fraction of the sector)*(area of the sector)
=1/(1/24)</span>×11.9
=285.6 m²