Answer:
8. Arithmetic Progression
9. 
Step-by-step explanation:
Given

Solving (8): Arithmetic or Geometric
We start by checking if it is arithmetic by checking for common difference (d).

This gives:



<em>Because the common difference is equal, then it is an arithmetic progression</em>
<em></em>
Solving (8):

To find f(9), we substitute 9 for n


We need to solve for f(8); substitute 8 for n


We need to solve for f(7); substitute 7 for n


We need to solve for f(6); substitute 6 for n


We need to solve for f(5); substitute 6 for n


From the function, f(4) = 25 and f(1) = 55.
So:














6 faces, 12 edges, and 8 vertices
Answer:
x = 3; y = 2
Step-by-step explanation:
x + y = 5
y = 2x - 4
<em>Isolate the y in the first equation</em>
y = 5 - x
y = 2x - 4
<em>Substitute the values</em>
5 - x = 2x - 4
<em>Isolate the Variable</em>
9 = 3x
<em>Simplify</em>
3 = x
<em>Plug that into the first equation</em>
3 + y = 5
<em>Subtract 3 from both sides</em>
y = 2
Sorry i need pointsss so 15 is your answer and i can leave