
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
Read the following material and complete the corresponding learning tasks. A student wrote the following calculation steps when calculating $2(ab^{2}+3a^{2}b)-3(ab^{2}+a^{2}b)$:

$2(ab^{2}+3a^{2}b)-3(ab^{2}+a^{2}b)$  
$=2ab^{2}+6a^{2}b-3ab^{2}-3a^{2}b\ldots$ Step 1  
$=2ab^{2}-3ab^{2}+6ab^{2}-3a^{2}b\ldots$ Step 2  
$=(2ab^{2}-3ab^{2})+(6a^{2}b-3a^{2}b)\ldots$ Step 3  
$=ab^{2}+3a^{2}b\ldots$ Step 4

Task 1:  
① The operation in the first step is ____, and the operation law used in this step is ____.  
② The operation law used in the second step is ____. The operation law used in the third step is ____.

Task 2:  
① An error occurred in step ____. Please write down the correct simplified result of the expression ____.  
② Calculate: When $a=-1$, $b=2$, find the value of the expression.

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