Question

Your EZ Pass account begins with $80. It costs you $4/day. Write an equation

for the amount in your account (A) in terms of the number of days (D).

Answer 1

The equation is
`A(d) = 80 - 4d`

Explanation:

Linear function:

A linear function for the amount of money in an account after t days is given by:

`A(d) = A(0) - md`

In which A(0) is the initial value and m is the daily cost.

Your EZ Pass account begins with $80. It costs you $4/day.

This means that
`A(0) = 80, m = 4`

So

`A(d) = A(0) - md`

`A(d) = 80 - 4d`