Each month Marla pays a $30 cell phone bill from her bank account. At the end of one year, what is the change in the amount of money in Marla's account
because of her cell phone bill? Write a multiplication equation to represent the
problem. Explain what the product represents.

monthly=30

yearly=30*12=360

-$360.00 change

Step-by-step explanation:

Now there is either some information missing, like her starting total in the bank; or they want you to explain the net change.  But the way the question is worded it is stating she is paying $30 over 12 months.  This means she has paid $360.00 in that 12 months aka 1 year.  Her bank account should have had a balance.  So you could technically say B for balance.  B-30*12.  To get your answer.  Although there are many ways to write an equation expression of this question.  If you know the starting balance then it's better.  But you could assume her starting balance was $0.  Which would be 0-30M*12 where M could represent monthly.  And the same answer would occur of 360.  Is there more information?

30*12= X (x equals the total paid)

X-30*12 (if x is her balance before paying any money)