
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
Determine an expression for the area of triangle $QCA$ in terms of $p$ and $x$ where:
- $Q(0, 15)$ is the top point on the y-axis,
- $A(x, 15)$ is directly to the right of $Q$ on the same horizontal line, $x > 0$,
- $C(0, p)$ is a point on the y-axis below $Q$, $0 < p < 15$.
You should simplify your answer as much as possible. 
Assume that $QA$ runs horizontally, and $QC$ acts as the height of $\triangle QCA$.

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