# the common zero of the polynomial x3 +1 , x2-1 and x2+2x+1 is

x^2 - 1 = (x+1)(x-1)

And, x^2+2x+1 = x^2 +x+x+1 = (x+1)(x+1)

so, x^3+1 = (x+1)(x^2-x+1)

x^2 - 1 = (x+1)(x-1)

x^2+2x+1 = (x+1)(x+1)

so, here, (x+1) is a common factor of all these polynomial.

it means that -1 is a common zero of all these 3 polynomial.

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