If P(Q−r)x2+Q(r−P)x+r(P−Q)=0 has equal roots then 2Q=(where P,Q,r ϵ R)
Product of the roots = 1 ⇒2Q=1P+1r
If p>q>0andpr<−1<qr, then find the value of
If every pair of the equations x2+px+qr=0 , x2+qx+rp=0 , x2+rx+pq=0 have a common root, then the sum of three common roots is