
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 odd function f(x) is defined on R, when x≤0, f(x)=x^2+4x.
(1) Find the analytic expression of f(x) and directly write out the monotonic interval of f(x);
(2) Find the solution set of the inequality f(x)>3.

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