
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 an ellipse C: $$\frac {x^{2}}{a^{2}} + \frac {y^{2}}{b^{2}} = 1$$ ($a > b > 0$) with an eccentricity of $$\frac { \sqrt {7}}{4}$$, and the length of its major axis is 8.  
(Ⅰ) Find the standard equation of ellipse C;  
(Ⅱ) If a line $l$ not perpendicular to the coordinate axes passes through point P($m$, 0) and intersects ellipse C at points A and B, with point Q having coordinates ($n$, 0), and the sum of the slopes of lines AQ and BQ equals 0, find the value of $mn$.

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