Answer:
The amount initially put (deposited) in the account is 800 + 350/x + 500/x² + 600/x³
Step-by-step explanation:
The annual interest rate by which the account grows = r
The factor by which the account grows annually = 1 + r
The function that provides the amount in the account after 4 years, given that the growth factor is x is given as follows;
A(x) = 800·x⁴ + 350·x³ + 500·x² + 600·x
The amount, P, initially put (deposited) in the account is given as follows;
P × (x)⁴ = 800·x⁴ + 350·x³ + 500·x² + 600·x
P = (800·x⁴ + 350·x³ + 500·x² + 600·x)/(x⁴) = 800 + 350/x + 500/x² + 600/x³
P = 800 + 350/x + 500/x² + 600/x³
The amount initially put (deposited) in the account = 800 + 350/x + 500/x² + 600/x³