
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
Below is the process of Wang Lei using the method of completing the square to solve a quadratic equation. Please read carefully and complete the corresponding tasks. Solve the equation: $x^{2}+4x-1=0$. 
$x^{2}+4x=1$... Step 1  
$x^{2}+4x+4=1+4$... Step 2  
$(x+4)^{2}=5$... Step 3  
$x+4=\pm \sqrt{5}$... Step 4  
${x}_{1}=-4+\sqrt{5}$, $x_{2}=-4-\sqrt{5}$... Step 5  
Task 1: Fill in the blanks: ① In the above solving process, step 2 is based on ______; ② Errors start to appear from step ______;  
Task 2: Please directly write down the correct roots of the equation as ______.

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