Find a method by which one can compute the coefficients of
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from the roots of
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by performing not more than

additions and

multiplications.
%V0
Find a method by which one can compute the coefficients of $P(x) = x^6 + a_1x^5 + \cdots+ a_6$ from the roots of $P(x) = 0$ by performing not more than $15$ additions and $15$ multiplications.