26 The n th term of a sequence is 9n + 4. (a) Calculate the value of the term that is closest to 2012. (b) Calculate the difference between the 10 th term and the 6 th term. (c) (i) Find an expression, in terms of x and y, for the difference between the x th term and they th term. (ii) Hence explain why it is not possible for any two terms of this sequence to differ by 123.