if the second term of an arithmetic sequence is 15 and the fifth term is 24. determine the third and fourth term of the sequence

Answer 1

a + (n-1) d

second is a + d = 15
fifth is a + 4 d = 24

so a = 15 - d
and
(15-d) + 4 d = 24
3 d = 9
d = 3
then a = 12
so term n is
12 + (n-1)3