
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
This year, the age of the older brother is twice the age of the younger brother. The younger brother said, "Six years ago, the sum of our ages was 15 years." If the age of the younger brother this year is $x$ years old, write the equation that describes the given situation.

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