How do u write the expanded form on 8374 using exponential notation

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.

Which one is the correct answer, and why?

Find the solution to this system 2,1 1,-2 1,2 -1,2