fig 1=
Given: 
Here, Either 
……….(i)
Or 
[Expanding along first row]
and 
and 
and 
and 
……….(ii)
Therefore, from eq. (i) and (ii), either or 
If a, b and c are real numbers, and fig 1 Show that either a+b+c=0 or a=b=c
If a, b and c are real numbers, and fig 1 Show that either a+b+c=0 or a=b=c