Answer:
a^2 + 2ab + b^2 - c^2
Step-by-step explanation:
When you multiply all the terms together you get a^2 + ab + ac + ab + b^2 + bc - ac - bc - c^2. Then you can just combine like terms and simplify it to a^2 + 2ab + b^2 - c^2. Hope this helps :)
The two parabolas intersect for

and so the base of each solid is the set

The side length of each cross section that coincides with B is equal to the vertical distance between the two parabolas,
. But since -2 ≤ x ≤ 2, this reduces to
.
a. Square cross sections will contribute a volume of

where ∆x is the thickness of the section. Then the volume would be

where we take advantage of symmetry in the first line.
b. For a semicircle, the side length we found earlier corresponds to diameter. Each semicircular cross section will contribute a volume of

We end up with the same integral as before except for the leading constant:

Using the result of part (a), the volume is

c. An equilateral triangle with side length s has area √3/4 s², hence the volume of a given section is

and using the result of part (a) again, the volume is

This question is tricky.
I think there would be B)24 people that would prefer Yellow :)
Well, the keyword here is One of the performers insist on being the last.
So, the amount of performers that we can arrange freely is 7 performers.
Different ways we can schedule their appearance is :
7 ! = 7 x 6 x 5 x 4 x 3 x 2 x 1
= 5040
hope this helps
A) A= 5000 x .0325 ( 31)
A= 5,037.50
.0325 = 3.25%
31 years 2021-1990 = 31