Answer:
f(n)= 5 · 4

Step-by-step explanation:
You use the explicit formula for geometric sequence. The five is the firat term and is placed correctly. The 4 is the rate of change, because if you multiply 5 by 4 you get 20 and so on.
Answer:

Step-by-step explanation:

-8 -8
₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋₋

⇵

Answer:
12
Step-by-step explanation:
If there are 3 classrooms that each have 25 desks and there are a total of 87 students, how many more desks need to be added to a 4th classroom, that was originally empty, so that each of the students has a desk to sit in?
25 * 3 = 75
87 - 75 = 12
Its a number or ratio expressed as a fraction of 100