Question

answer the following

Answer 1

[ a+b b+c c+a ] = ((a+b). (b+c))×(c+a) expanding
= ((a.b)+(a.c)+(b.b)+(b.c))×(c+a) expanding
= ((a.b)×c)+((a.c)×c+((b.b)×c)+((b.c)×c) + ((a.b)×a)+((a.c)×a)+((b.b)×a)+((b.c)×a)
= [ a b c ]+[ a c c ]+[ b b c ]+[ a c c ] + [ a b a ]+[ a c a ]+[ b b a ]+[ b c a ]
= [ a b c ] + [ b c a ]
= [ a b c ]+[ a b c ]
= 2[ a b c ]