因式分（x+y）2-3（x+y）=______．
（x+y）2-3（x+y）=（x+y）（x+y-3）．
已知点A（a，2）是点B（3，b）关于原点O的对称点，求出a+b的值是______．
In relation to the formation of a company explain:
(a) the role and duties of promoters, and how they are regulated; (5 marks)
