5k3-3k+7-(-2k3+k2-9) basically rewrite with simple algebra principles 15k-3k+7-(-6k+2k-9) split up the parenthesis 15k-3k+7+6k-2k+9 sort them 15k-3k+6k-3k+7+9 short down by adding up the similar factors answer: 18k+18 factorise 18(k+1) both forms are right
