(a2+c2−b2) ‌⇒a2(b2+c2−a2)=b2(a2+c2−b2) ‌⇒a2b2+a2c2−a4=a2b2+b2c2−b4 ‌⇒a4−b4+b2c2−a2c2=0 ‌⇒(a2−b2)(a2+b2)+c2(b2−a2)=0 ‌⇒(a2−b2)[a2+b2−c2]=0 ‌‌ As ‌(a≠b),a2−b2≠0 ‌a2+b2−c2=0⇒a2+b2=c2 ∴△ABC is a right angled triangle with AB as hypotenuse.