The roots of the given equation (p−q)x2+(q−r)x+(r−p)=0 are
(p−q)x2+(q−r)+(r−p)=0
(p−q)x2+(q−p)x+(p−r)x+(r−p)=0
(p−q)x(x−1)+(p−r)(x−1)=0
((p−q)x+(p−r))(x−1)=0
x=−(p−r)p−q,x=1
x=r−pp−q,x=1