How do I solve 3x-y=15

Marco has $38.43 dollars in his checking account. his checking account is linked to his amazon music account so he can buy music. the songs he purchases cost $1.29. part 1: write an expression to describe the amount of money in his checking account in relationship to the number of songs he purchases. part 2: describe what the variable represents in this situation.

Iam at home. /: i am playing video games. translate the following statement into symbolic form.

How can writing phrases as algebraic expressions you solve problems?