
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 a function $f(x) = mx^3 + nx^2$, the graph of the function at point $(-1, 2)$ has a tangent line that is exactly parallel to the line $3x+y=0$.
(1) Find the range of the function $f(x)$ on the interval $[-4, 0]$.
(2) If $f(x)$ is monotonically decreasing on the interval $[t, t+1]$, find the range of the real number $t$.

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