Question

$a=18t+15$
Jane made an initial deposit to a savings account. Each week thereafter she deposited a fixed amount to the account. The equation above models the amount $a$, in dollars, that Jane has deposited after $t$ weekly deposits. According to the model, how many dollars was Janes initial deposit? (Disregard the $ sign when gridding your answer.)

Answer 1

From the equation, we can understand that the total $a$ dollars is equal to the sum of $15$ dollars and the amount of $18$ dollars deposited by Jane every week for $t$ weeks.
Thus, the initial deposit made was $15$ dollars.