The sixth term of an arithmetic sequence is 8 and the sum of the first 15 terms is 60. Find the common difference and list the first three terms.
Formulae to be used: nth term of an arithmetic sequence un= u1 + (n-1)d and sum of the first n terms of an arithmetic series Sn = (n/2) * (2u1 + (n-1)d) Substitute known values: u1 + 5d = 8(15/2) * (2u1 + 14d) = 60 Attempt to solve simultaneous equations, by eliminating u1 and d, in turn, to get d = -2, and u1 = 18, u2 = 16, u3 = 14.
