[ a + b b + c c + a ] is equal to

Step-by-step solution

aligned & [ a + b b =+ a & =( a + b ) [( b + c ) ( c + a )] & =( a + b ) [( b c + b a +0+ c a )] aligned aligned & =[ a b c ]+0+0+0+0+[ b c a ] & =[ a b c ]+[ a b c ] & =2[ a b c ] aligned