a_n = a_ (n-1) +d
a) 2,8,14,.......
b) 8-2 =6
14-8 =6
d=6
c) a_n = a_ (n-1) +8
check:
a_1 = 2
a_2 = a_ 1 +6 = 2+6 =8
2_3 = a_2 + 6 = 8 + 6=14
a_n = a_ (n-1) +8
