Geometric sequences go up due to a common ratio. Here the common ratio can be worked out by dividing a term by its previous term e.g term 2 divided by term 1.

Therefore the common ratio is 6.
Number one ☝️ right maybe
A cosine is just a sine shifted to the left by π/2. A cosine of 4x is shifted to the left by only π/8 because of the factor 4. Sketch them.
The region we're looking for is this sausage-shaped part between the cos and the sin.
The x intercepts are at π/8 for the cosine and π/4 for the sine. The midpoint between them is at (π/8 + π/4)/2 = 3/16π.
The region is point symmetric around the x axis, so the y coordinate of the centroid is 0.
So the centroid is at (3/16π, 0)
answer would be the second one: Rectangle that is not a square
-2n-24=-8(2n-4)
Multiply both sides by -1
2n+24=8(2n-4)
Distribute the right side
2n+24=16n-32
Subtract 2n from both sides
24=14n-32
Add 32 to both sides
56=14n
Divide 14 from both sides
n=4