Which of the following correctly expresses the number in scientific notation 645,000,000

Diane owes $387 to her brother. if she debits her bank account $161.25 a month to pay him back, how many months will it take her to pay off the debt?

Ineed if you could explain and give me the answer you! this needs done

Solving systems of linear equations: tables represent two linear functions in a systemöwhat is the solution to this system? 0 (10)0 (1.6)0 18,26)0 18-22)