Find the 139th term of the arithmetic sequence whose first term is -28 and the common difference is 1/3
a139 = a1 + d ( n -1)
So we have
a139 = -28 - (1/3) ( n - 1)
a139 = -28 - (1/3)(139) + 1/3 = -28 - 139/3 + 1/3 = -28 - 138/3 = -28 - 46 = - 74
