3 + 9x A B 3 (a) Express in the form (1 +x) (3+5x) 1+x 3+ 5x' where A and B are integers. 3 +9x (b) Hence, or otherwise, find the binomial expansion of up to and (1 + x) (3+5x) including the term in x2. Find the range of values of x for which the binomial expansion of 3+9x (c) is (1 + x) (3 + 5x) valid