
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
In the Cartesian coordinate system, $O$ is the origin. Given two points $A(2,1)$, $B(-1,-2)$, if point $C$ satisfies $\overrightarrow{OC} = s \overrightarrow{OA} + t \overrightarrow{OB}$, and $s+t=1$, then the equation of the trajectory of point $C$ is ______.

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