2x^2+2.2x.1+1^2-(2x^2-2.2x.1+1^2)
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X^2+2.x.1+1^2-(x^2+2.x.1+1^2)
2x^2 + 4x +1 - (4x - 4x +1)
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X^2 +4x +1 - (x^2 +4x +1)
4x +4x +1 - 4x +4x - 1
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X^2 + 4x + 1 - x^2 - 4 x - 1
4x