X^5+2x^4-3x^3-3x^2+x+1=0

x^4 (x+1) — 3x^2 (x+1)+(x+1)=0 (x+1) (x^4 — 3x^2+1)=0x+1=0 -> x=-1x^4 — 3x^2+1=0 -> D=9-4=5 -> x^2=(3+sqrt5) /2 -> x=sqrt (3+sqrt5) /2) , x=-sqrt (3+sqrt5) /2) x^2=(3-sqrt5) /2 -> x=sqrt (3-sqrt5) /2) , x=-sqrt (3-sqrt5) /2)