
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 circle $C: x^{2}+y^{2}+4x-12y+24=0$ and a line $l: y=kx+5$.<br/>$(1)$ If the chord intercepted by line $l$ on circle $C$ has a length of $4\sqrt{3}$, find the equation of line $l$;<br/>$(2)$ If line $l$ intersects circle $C$ at points $A$ and $B$, find the equation of the locus of the midpoint $M$ of $AB$.

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