
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 $\left\{a_{n}\right\}$ that satisfies $(a_{3}=7)$, $(a_{5}+a_{7}=26)$, and its sum of the first $n$ terms is denoted as $(S_{n})$.

(1) Find $(a_{n})$ and $(S_{n})$;
(2) Let $(b_{n}=\frac{1}{a_{n}^{2}-1}\left(n∈\mathbb{N}^{*}\right))$, find the sum of the first $n$ terms of the sequence $\left\{b_{n}\right\}$, denoted as $(T_{n})$.

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