We can expand \((a-b)^2\) using the formula \((x-y)^2 = x^2 - 2xy + y^2\):
\[
(a-b)^2 = a^2 - 2ab + b^2
\]
Now, substituting this back into the expression gives:
\[
a^2 - 2ab + b^2 + 4ab = a^2 + 2ab + b^2
\]
Next, we recognize that \(a^2 + 2ab + b^2\) is a perfect
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