Given equations are x2+ax+bc=0 and x2+bx+ca=0 On subtracting equation second from equation first ∴(a−b)x+c(b−a)=0 ⇒(a−b)(x−c)=0 ⇒x=c is the common root. Thus, the roots of x2+ax+bc=0 are b and c and that of x2+bx+ca=0 are c and a. It roots are b and a, then equation will be x2−(a+b)x+ab=0