
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 set \( A = \left\{ x \mid \frac{x+4}{x-3} \leqslant 0, x \in \mathbf{Z} \right\} \). Selecting an element \( x \) randomly from set \( A \), let \( \xi = x^2 \). Find the expected value \( \mathrm{E}(\xi) \) of the random variable \( \xi \).

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