
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 domain of the function $f(x)$ be $(-4, 4)$, and the domain of the function $f(2x)$ be the set $A$. Let set $B=\{x | x^2 - x + a - a^2 < 0\}$, where $a < 0$.  
(1) If $A \cup B = B$, find the range of values for $a$;  
(2) If $A \cap B = B$, find the range of values for $a$.

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