For example, we know that $x^5-x+1$ is a polynomial of degree five over $\mathbb Q$ that is not solvable by radicals. Which means that one of the roots of this polynomial is not in root closure of $\mathbb Q$. Is there a polynomial whose coefficients in $\mathbb Q$ such that none of the roots of this polynomial be in the root closure of $\mathbb Q$? In the other hand, can we find a polynomial over $\mathbb Q$ such that none of the roots of this polynomial Obtained by the operations multiplying, suming, Subtracting, Divising and rooting from elements of $\mathbb Q$
Is there a polynomial whose Coefficients in $\mathbb Q$ such that none of roots of this polynomial be in the root closure of $\mathbb Q$?
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galois-theory
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0Thnaks for your answer, can we find a reference for your Theorem? – 2017-01-01
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1It's probably in Stewart's textbook, Galois Theory. – 2017-01-01