It is known that α, β and γ are rational numbers and α + β + γ = 0, then α & sup2; + β & sup2; + γ & sup2; - β γ ‐ γ α ‐ α β = ()

It is known that α, β and γ are rational numbers and α + β + γ = 0, then α & sup2; + β & sup2; + γ & sup2; - β γ ‐ γ α ‐ α β = ()

α²+β²+γ²‐βγ‐γα‐αβ=1/2×2(α²+β²+γ²‐βγ‐γα‐αβ)=1/2×(α²+β²+γ²+α²+β²+γ²‐2βγ‐2γα‐2αβ)=1/2...