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Algebra Difficulty 4.8 AIME Prove it United States

Problem:
Suppose xx satisfies x3+x2+x+1=0x^{3}+x^{2}+x+1=0. What are all possible values of x4+2x3+2x2+2x+1x^{4}+2 x^{3}+2 x^{2}+2 x+1?

Solution

Solution:
x4+2x3+2x2+2x+1=(x+1)(x3+x2+x+1)=0x^{4}+2 x^{3}+2 x^{2}+2 x+1 = (x+1)\left(x^{3}+x^{2}+x+1\right) = 0 is the only possible solution.

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