Question

if a + b + c =zero then a square ÷be + b square ÷ ca +c square ÷ ab

Answer 1

a+b+c)2 = a2 + b2+c2+2(ab + bc+ca)let  (ab + bc+ca) be x(0)2 = 20 + 2(x)-20 =2x-20/2 = x-10 = xTherefore ab+ bc+ca = -10