Answer:
3n + 3
Step-by-step explanation:
Mia is correct
When n= 1 , 3n + 3 = 3*1 + 3 = 3 + 3 = 6
When n =2, 3n + 3 = 3*2 + 3 = 6 + 3 = 9
When n = 3 , 3n +3 = 3*3 + 3 = 9 + 3 = 12
When n = 4, 3n + 3 = 3*4 + 3 = 12 +3 = 15
