13 (a) 2, e, f, 20, … A linear sequence has a first term of 2 and a fourth term of 20. The term-to-term rule for this sequence is add k. W ork out the values of e, f and k. e = ....................................................... f = ....................................................... k = ....................................................... [3] (b) These are the first four terms of another sequence. 9 7 5 3 Find the nth term. ................................................. [2] M SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TON OD NIGRAM SIHT NI ETIRW TO