
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
If \(A = \{x^2, 2x-1, -4\}\) and \(B = \{x-5, 1-x, 9\}\), with \(B \cap A = \{9\}\),  
(1) Find the value of \(x\),  
(2) Find \(A \cup B\).

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