
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
Let  $a_1,a_2,a_3,\dots,a_6$  be an arithmetic sequence with common difference  $3$ . Suppose that  $a_1$ ,  $a_3$ , and  $a_6$  also form a geometric sequence. Compute  $a_1$ .

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