Q.
Let α1,α2 and β1,β2 are roots of the equation ax2+bx+c=0 and px2+qx+r=0 respectively. If the system of equations α1y+α2z=0 and β1y+β2z=0 has a non trivial solution, then
∣∣α1β1α2β2∣∣=0⇒α1β2−α2β1=0⇒α2α1=β2β1
Using componendo and dividendo α1−α2α1+α2=β1−β2β1+β2⇒a2b2−a4c−b/a=p2q2−p4r−q/p ⇒b2−4acb=q2−4prq⇒b2pr=q2ac