
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 the speed of the fast horse is twice that of the slow horse, find the equation that represents the specified time x, where the slow horse takes 1 day longer than the specified time to deliver a document 900 miles away, and the fast horse takes 3 days less than the specified time.

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