
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 that $f(x)$ is an odd function defined on $\mathbb{R}$, and $f(x) = 1 - 3^x$ when $x > 0$.
1. Find the expression of function $f(x)$ and determine its monotonicity (without proof).
2. The inequality $f(\log_2^2 x) + f(5 - a \log_2 x) \geq 0$ always holds when $x \in [2, 8]$. Find the range of values for the real number $a$.

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