Quintic polynomials are polynomials of degree 5. Like with cubic polynomials, Descartes' method to solving the roots of quintic functions is the same as that of solving the roots of sextic functions (polynomials of degree 5). Simply multiply the quintic polynomial through by x creating a sextic polynomial and then follow the steps to solving the roots of the sextic function (you can find that here). When you do this, ignore the x=0 solution. (Rubinstein, 6)
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