
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 function $f(x)$ defined on $R$ satisfies $f(x) - f(-x) = 0$, and $\frac{f(x_{1}) - f(x_{2})}{x_{1} - x_{2}} < 0$ always holds on $(-\infty, 0]$, determine the solution set of the inequality $f(x - 1) < f(3)$.

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