
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: $A=2a^{2}+3ab-2a-1$, $B=a^{2}+ab-1$  
$(1)$ Find the value of $4A-\left(3A-2B\right)$.  
$(2)$ When $a$ takes any value, and the value of $A-2B$ is a constant, find the value of $b$.

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