The polynomial expression which represents the value of the account at the end of three years is 1000x³ + 300x² + 500x
Interest earned per year, x = 1 + r
First year :
Year end balance = 1000 × x = 1000x
Second year :
Year end balance = (1000x + 300)x = 1000x² + 300x
Third year :
Year end balance = (1000x² + 300x + 500)x = 1000x³ + 300x² + 500x
Therefore, the expression which represents the value of the account at the end of three years is 1000x³ + 300x² + 500
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