Terrence is not correct.
Terrence is not correct because pi is an irrational number, and it goes on forever with no actual sequence.
They are essentially asking us to solve:

Solving this equation for x tells us that it will take around 80.1 years for the materials in the vault to reduce to 357 pounds.
Answer:
-5/9
Step-by-step explanation:
9(x+1)=4-2(9x+5)
Distribute
9x+9=4-18x-10
Add 4 and -10
9x+9=-6-18x
Move -18 to the left side and change sign
9x+9+18x=-6
Move 9 over and change sign
9x+18x=-6-9
Combine like terms
27x=-15
Divide both sides by 27
X=-5/9
1. Use Difference of squares: a^2-b^2=(a+b)(a-b)
(x+k)(x-k)=0
2. Solve for x and k
x=+-k
k=+-x
14.9682539683 Your welcome have a good day!