α,β,γ are the root of x3−2x2−x+2=0. Centroid of triangle with verties α,β,γ, (β,γ,α),(γ,α,β) is
−23,23,−23
−23,13,23
23,23,23
43,23,23
s1=α+β+γ=2
s2=αβ+βγ+γα=−1
α+β+γ3,α+β+γ3,α+β+γ3