I dont know how to solve 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.

Average acceleration: i have no idea how to do this.

Find the equation of the line with slope =8 and passing through (6,53) write your equation in the form y=mx+b