Answer :
a) We have the following arithmetic sequence:
f(n) = 25 + (n - 1)(7)
The first five terms are given by n = 1,2,3,4 and 5. Replace these values of n into the previous formula:
f(1) = 25 + (1 - 1)(7) = 25 + 0 = 25
f(2) = 25 + (2 - 1)(7) = 25 + 7 = 32
f(3) = 25 + (3 - 1)(7) = 25 + 14 = 39
f(4) = 25 + (4 - 1)(7) = 25 + 21 = 46
f(5) = 25 + (5 - 1)(7) = 25 + 28 = 53
Hence, the first terms are 25, 32, 39, 46 and 53