
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
If the axes of symmetry of an ellipse are the coordinate axes, and the sum of the lengths of the major and minor axes is 18, and one of the foci is at (3, 0), determine the standard equation of the ellipse.

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