
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
Define a new operation "$\star$" by $x \star y = 5x - 4y + 2xy$ for all real numbers $x$ and $y$. Determine the number of real numbers $y$ such that $4 \star y = 10$.
A) -2.5  
B) 0  
C) 2.5  
D) 5  
E) Infinite solutions

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