Answer:
3+3+3+3
Explanation:
the answer is addition because if you add those they just its 12 cause thats 3x4 but if its 3 by 3 four times thats 81 and 3 to the fourth power thats 81 and last 3 squared twice multiplied by each other is 81
Hope this explains it im not very good at explanations but i tried lol