
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
The function f(x) is defined as follows:

$$
f(x) =
\begin{cases}
x^2 + 1, & \text{if } x \leq 0 \\
-3x, & \text{if } x > 0
\end{cases}
$$

If $f[f(x)] = 10$, then $x$ is $\_\_\_\_\_\_$.

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