can you show me the working with correct answer?

SET 1 QUESTION 1 (a) The sum of the first n terms of an arithmetic series is - (Sn? -n). (i) Write down an expression for the sum of the first n -1 terms. [ 2 marks ] (C2, CLO1, MQF LOD1) (ii) Hence, show that the series is an arithmetic series. [ 3 marks ] (C2, CLO1, MQF LOD1) (b) The sixth term and the third term of a geometric series are - and 1 486 18 respectively. (i) Find the common ratio of the series. [ 2 marks ] (C2, CLO1, MQF LOD1) (ii) Determine the smallest integer value n such that Soo - S, in three significant figures. [ 4 marks ] (C2, CLO1, MQF LODI)