
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 the sets $A = \{ x | x^2 - x - a = 0 \}$ and $B = \{ 2, -5 \}$, with $2 \in A$:
(I) Find the value of $a$ and list all elements of set $A$;
(II) Let the universal set $U = A \cup B$, find $(\complement_U A) \cup (\complement_U B)$.

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