Question

$(a-3b{)}^3+(3b-c{)}^3+(c-a{)}^3$

Answer 1

$(a-3b{)}^3+(3b-c{)}^3+(c-a{)}^3\because a-3b+3b-c+c-a=0\therefore (a-3b{)}^3+(3b-c{)}^3+(c-a{)}^3=3(a-3b)(3b-c)(c-a)\{\because a^3+b^3+c^3=3abcifa+b+c=0\}$