
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
18. Given the function $f(x)=x^3+ax^2+bx+5$, the equation of the tangent line to the curve $y=f(x)$ at the point $x=1$ is $3x-y+1=0$.

Ⅰ. Find the values of $a$ and $b$;

Ⅱ. Find the maximum and minimum values of $y=f(x)$ on the interval $[-3,1]$.

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