
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 that the moving circle $P$ is tangent to the circle $F\_1: (x+3)^2 + y^2 = 81$ and internally tangent to the circle $F\_2: (x-3)^2 + y^2 = 1$, denote the trajectory of the center of circle $P$ as curve $C$. Find the equation of curve $C$.

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