
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 algebraic expression $\left(ax-3\right)\left(2x+4\right)-x^{2}-b$ after simplification, it does not contain the terms $x^{2}$ and the constant term.<br/>$(1)$ Find the values of $a$ and $b$.<br/>$(2)$ Find the value of $\left(2a+b\right)^{2}-\left(2-2b\right)\left(2+2b\right)-3a\left(a-b\right)$.

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