
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 the operation "$\circ$" by $x \circ y = 5x - 4y + 3xy$ for all real numbers $x$ and $y$. Find $y$ such that $4 \circ y = 21$.
A) $\frac{1}{6}$
B) $\frac{1}{7}$
C) $\frac{1}{8}$
D) $\frac{1}{9}$
E) $\frac{1}{10}$

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