The equation editor is not properly working so i write in the normal text.
b^2- 4 ac = (p+q)^2 - 4 pq = (p-q)^2
If the roots of the given equation both are equal, then the discriminant is 0.
then (p-q)^2 = 0. Hence p = q.
if p= q, then equation will be x^+2x+1=0, hence roots are equal and = -1.
If p > q and q > p -- in these case real roots exist but they are not equal.