
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 the function $f(x)=ax^{2}-(a+2)x+\ln x+b$ ($a > 0$).  
(1) If the tangent line of the function $f(x)$ at $x=1$ is $y=x-1$, find the values of the real numbers $a$ and $b$.  
(2) Under the condition of (1), when $a \geqslant 2$, discuss the number of zeros of the function $f(x)$.

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