
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
It is known that function $f(x) = ax^2 + bx$.
(i) If the tangent to the function $f(x)$ at $x=3$ is parallel to the line $24x-y+1=0$, and $f(x)$ attains an extreme value at $x=1$, find the decreasing interval of $f(x)$;
(ii) If $a=1$, and the function $f(x)$ is decreasing on the interval $[-1,1]$, find the range of values for the real number $b$.

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