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"?

2 Answers
Jan 23, 2016

Let's call the amount spent #s#


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):

Jan 23, 2016

40 - a = d


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