Answer:
The expression that is equivalent to the given expression is:
  5x+60
Explanation:
It is given that:
if you add 12 marshmallows to each of 5 bags of marshmallows, and each bag started with the same number of marshmallows.
so, let x be the initial number of marshmallows in each bag and now 12 are added to each bag this means that the number of marshmallows in each bag is:
 x+12
Hence, total number of marshmallows in 5 bags is:
 5(x+12)=5×x+5×12
 5(x+12)=5x+60
  Hence, the answer is:
 5x+60