
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 function $$f(x)= \begin{cases} (3a-1)x+4a & x<1 \\ \log_{a}x & x\geq 1\end{cases}$$, if $a=2$, find $f(f(2))= \_\_\_\_\_$; if $f(x)$ is a monotonic function on $\mathbb{R}$, then the range of values for $a$ is $\_\_\_\_\_$.

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