
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
In acute triangle $\triangle ABC$, the sides opposite angles $A$, $B$, $C$ are denoted as $a$, $b$, $c$, respectively. Given that $\frac{\sin A - \sin B}{\sqrt{3}a - c} = \frac{\sin C}{a + b}$. Find:<br/>
$(1)$ the value of angle $B$;<br/>
$(2)$ if $a = 2$, find the range of possible values for the perimeter of triangle $\triangle ABC$.

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