
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 a function $f(x)$ that satisfies $f(x) + 2f(-x) = -3x - 6$.  
$(1)$ Find the analytical expression of $f(x)$.  
$(2)$ Find the range of the function $g(x) = xf(x)$ on the interval $[0,3]$.

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