If the roots of the equation (a2−bc)x2+2(b2−ac)x+c2−ab=0 are equal, then
b = 0
a3 + b3 + c3 = 3abc
Roots of the equation are equal
⇒Discriminant = 0
D=(2(b2−ac))2−4(a2−bc)(c2−ab)
=4[(b2−ac)2−(a2−bc)(c2−ab)]
=4[b4+a2c2−2b2ac−a2c2+a3b−b2ac+bc3]
=4[b4+a3b+bc3−3b2ac]
D=0
⇒b(b3+a3+c3−3abc)=0
⇒b=0 or b3+a3+c3−3abc=0