Answer:
$577
Explanation:
Let y = amount of money in the account.
Let x = number of months.
The withdrawals are always the same amount and occur every month, so this is a linear relation.
We are given two points of the relation: (5, 442) and (13, 226).
y = mx + b
m = (442 - 226)/(5 - 13) = 216/(-8) = -27
The slope, -27, represents the amount she withdraws each month.
y = -27x + b
442 = -27(5) + b
442 = -135 + b
b = 577
y = -27x + 577
b = y-intercept = initial amount
Answer: The input was $577.