
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
Evaluate the following:

(1) Simplify and then evaluate: $(x-5y)(-x-5y)-( -x+5y)^2$, where $x=0.5$, $y=-1$;

(2) Given $a^2 -2a + b^2 + 4b + 5 = 0$, find the value of $(a+b)^{2013}$.

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