If α, β, γ are the roots of px3+qx2+r=0, then the value of the determinant αβ βγ γαβγ γα αβγα αβ βγ is
p
q
0
r
Operation C1→C1+C2+C3 gives
(αβ+βγ+γα)1βγγα1γααβ1αββγ
From the given equation, αβ+βγ+γα=0. So, the value of determinant is 0.