I believe the answer is 84x.
1. Combine the like terms which is 4x, 8x, and 8x.
2. Add them and you’ll get 84x.
Answer:

Explanation:
[ Step One ] Remove Parenthesis: (a) = a

[ Step Two ] Multiply: 

[ Step Three ] Apply Exponent Rule 

[ Step Four ] Apply Exponent Rule: 

[
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The answer is negative twelve -12
Hope this helps