1. The problem statement, all variables and given/known data If : p2+q2+4r2 = pq+2qr+2rp Prove that : p=q=2r 2. Relevant equations I am not sure but I tried using this equation : (a+b+c)2 = a2+b2+c2+2(ab+bc+ca) 3. The attempt at a solution p2+q2+4r2 = pq+2qr+2rp p2+q2+4r2 -pq-2qr-2rp = 0 Now I can't factor. Its not yielding correct answer. Please help.