If every pair among the equations x2+px+qr=0, x2+qx+rp=0 and x2+rx+pq=0 have a common root, then (sumofroots)(productofroots) =
x2+qx+rp=0 ; α,β
x2+px+rq=0 ; β,γ
x2+rx+pq=0 ; γ,α
Then, β2+qβ+rp=0,β2+pβ+qr=0
⇒(q−p)β = r(q-p) ⇒ β = r.
Similarly , γ=q,α=p .
∴ (α+β+γ)αβγ = (p+q+r)pqr .