Simplify (x^4 + x^3 + x^2 + x + 1) + (x^4 - x^3 + x^2 - x + 1).
stack them for addition
x4 + x3 + x2 + x + 1
x4 – x3 + x2 – x + 1
2x4 + 2x2 + 2 = 2(x4 + x2 + 1)
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