2 x (5-2)^3
2 x (3)^3
2 x 27
54
2n + 1
the number before n is the difference (what it goes up in), and the second is the ‘zeroth’ term: you take away the 2 you got from the first value, 3, and get 1 :)
Answer:
-1 1/24
Step-by-step explanation:

There are 4 red billings/billions. (Not sure what the correct word is since you use two different words.)
The answer is:
50(16n+21)