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factorize

factorize:
x^5 + x + 1
Reply 1
Original post by Soustav
factorize:
x^5 + x + 1


Have you tried factorizing it into a product of a quadratic and a cubic?

What is your level, what techniques have you tried?
Reply 2
x^5 + x + 1
= x^5 - x^2 + x^2 + x + 1
= x^2(x^3 - 1) + 1(x^2 + x + 1)
= x^2(x-1)(x^2 + x + 1) + 1(x^2 + x + 1)
= (x^2 + x + 1){ x^2(x-1) + 1}
x^5 + x + 1
= x^5 - x^4 + x^4 - x^3 + x^ 3 - x^2 +x^2+x+1
=x^4(x-1) + x^3(x-1) + x^2 (x - 1)+ x^ 2+ x +1
=(x-1)(x^4+x^3+x^2)+(x^2+x+1)
=(x-1)(x^2)(x^2+x+1)+(x^2+x+1)
=(x^2+x+1)(1+(x-1)*x^2)
=(x^2 + x + 1)(x^3 - x^2 + 1)

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