
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
Let the function $f(x)$ be a differentiable function defined on $(-\infty,0)$, with its derivative denoted as $f′(x)$, and it satisfies $3f(x)+xf′(x) > 0$. Determine the solution set of the inequality $(x+2015)^{3}f(x+2015)+27f(-3) > 0$.

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