
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 $\{a\_n\}$, $a\_1=25$, and $S\_17=S\_9$.
(1) Find the general term formula for $\{a\_n\}$;
(2) How many terms at the beginning of this sequence have the maximum sum? Also, find this maximum sum.

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