Question

How do you write an algebraic expression that models the word phrase "The amount of money you spent if you started with $40 and now have d dollars"?

Answer 1

Let's call the amount spent `s`

Explanation:

We know that the amount spent and the amount left adds up to `$40`, or in formula-form: `s+d=40`

Or in another form (by subtracting `d` on both sides):
`s=40-d`

Answer 2

40 - a = d

Explanation:

let the amount of money spent be a

started with 40 and spent a is represented by : 40 - a

left with d , hence 40 - a = d