
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 triangle ABC, the sides opposite to angles A, B, C are a, b, c respectively. Given that 2sin Bsin C + cos B + 2cos(B + C) = 0, and sin B ≠ 1.

1. Find angle C.
2. If 5sin B = 3sin A, and the area of triangle ABC is $\frac{15\sqrt{3}}{4}$, find the perimeter of triangle ABC.

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