
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 quadratic function $y=ax^2+bx-3$ whose graph passes through points A(2, -3) and B(-1, 0).

(1) Find the expression of the quadratic function;  
(2) Fill in the blank: To make the graph of the quadratic function have only one intersection point with the x-axis, the graph should be moved upward along the y-axis by $\boxed{\text{units}}$.

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