
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<sub>n</sub>} with the sum of its first n terms denoted as S<sub>n</sub>, if S<sub>3</sub> = 9 and S<sub>6</sub> = 36, find the value of a<sub>7</sub> + a<sub>8</sub> + a<sub>9</sub>.

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