4. Expand each of the following, using suitable identities:(i) (x + 2y + 4z)²(ii) (2x – y + z)²(iii) (–2x + 3y + 2z)²(iv) (3a – 7b – c)²(v) (–2x + 5y – 3z)²(vi) [ (1/4)a – (1/2)b + 1 ]²