\(\mbox{There is no constant term so clearly }x=0 \mbox{ is one of the roots.}\\ \mbox{Dividing through by }x-0=x \mbox{ we get} \\ x^3-5x^2 +3x+1 = 0 \\ \mbox{Because the constant term is 1 if anything divides this polynomial it will be }(x-1) \mbox{ or }(x+1) \\ \mbox{Checking }(x-1)\mbox{ we plug 1 in and see if it works}\\ 1-5+3+1 = 0 \mbox{ so }1 \mbox{ is indeed a root. Dividing by }(x-1) \mbox{we get}\\ x^2-4 x-1\\ \)
\(\mbox{This can't be factored over rational numbers so we'll have to use the quadratic formula.}\\ r=\dfrac{-b\pm \sqrt{b^2-4ac}}{2a} \\ a=1, b=-4, c=-1 \\ r_1=\dfrac{4+\sqrt{16+4}}{2}= (2+\sqrt{5}) \\ r_2 =\dfrac{4-\sqrt{16+4}}{2}= (2-\sqrt{5})\)
\(\mbox{So gathering all this up we have roots of } \\ x \in \{0,1,2+\sqrt{5},2-\sqrt{5}\}\)
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