Write a recursive formula for the sequence 5 18 31 44 57 then find the next term

an= a1 + d(n−1)

where

a1 is the first term

d is the common difference 

n is the number of terms

in this problem

a1=5

a2=18

a3=31

a4=44

a5=57

so

d=a2-a1 or a3-a2 or a4-a3 or a5-a4

d=57-44> 13

find a6

a6= a1 + d(n−1)

n=6

d=13

a1=5

a6=5+13*(6-1)> a6=5+13*5> a6=70

the answer is

a6=70