
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 $\left\{a_{n}\right\}$ with the following conditions: $a_{3}=7$, $a_{5}+a_{7}=26$, and the sum of the first $n$ terms of the sequence is denoted as $S_{n}$.

(1) Find $a_{n}$ and $S_{n}$.

(2) Let $\dfrac{1}{b_{n}}=a_{n}^{2}-1\left(n\in N^{*}\right)$, determine 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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