
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
Given an arithmetic sequence $\{a_n\}$ where the sum of the first 3 terms is 6 and the sum of the first 8 terms is -4.
(Ⅰ) Find the general formula for the term $a_n$;
(Ⅱ) Let $b_n = (4-a_n) \cdot 3^n$, find the sum of the first n terms of the sequence $\{b_n\}$, denoted by $S_n$.

Present the answer in LaTex format: \boxed{Your answer}
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