Question:
Harry took a loan from the bank. D represents Harry's remaining debt (in USD) after t months.
What was the size of Harry's loan?
Answer:
Remember that when modeling a problem like this with the general formula for linear equations:
m represents a quantity that varies, and b is a fixed quantity.
For this problem, that would mean that Harry took a loan of $9,000 , and that he's paying $200 to the bank each month to cover his loan.
Therefore, Harry's loan was $9,000