Pls help!! and show your work. i'm confused on it

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.

Jan accidently ran 7 minutes longer than he was supposed to. write an expression for the total amount of time jan ran if she was supposed to run m minutes

Ineed some on this. not sure how to solve.