
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 a function $f(x) = \ln x + bx - c$, the equation of the tangent line to $f(x)$ at the point $(1, f(1))$ is $x + y + 4 = 0$.
(1) Find the explicit formula for $f(x)$;
(2) Determine the intervals of monotonicity for $f(x)$;
(3) If for the interval $\left[\frac{1}{2}, 3\right]$, it always holds that $f(x) \geq 2\ln x + kx$, find the range of $k$.

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