
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
In the arithmetic sequence $\{a\_n\}$, it is known that $a\_1+a\_2+a\_3=21$, $a\_1a\_2a\_3=231$.
(1) Find the value of $a\_2$ in this sequence;
(2) Find the general term formula $a\_n$ of this sequence.

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