Question 1207185
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Notice that the years in the table are given with the constant step of 5 years.


From your table, calculate the ratio of the next term balance to the previous term balance.


I did it and obtained a constant value of 1.1592 (rounded) for all adjacent terms.


The fact that the consecutive fractions have constant values tells that the function is exponential.
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That's all.


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As an additional clue, you may use the fact that banks use 
either linear function (simple percent account) or exponential functions (compounded accounts).
They never use quadratic functions or absolute value functions as growth functions,
so for you in this problem the choice is, actually, between linear and exponential, only.



There is no any need to inflate this bubble to incredible proportions.