Answer:
17 + 3n
Step-by-step explanation:
20, 23,26 ..............
This is an arithmetic series
First term = a = 20
Common difference = second term - first term
d = 23 - 20 = 3
nth terms = a + (n-1)*d
= 20 + (n -1) *3
= 20 + n*3 - 1*3
= 20 + 3n - 3
= 20 - 3 + 3n
= 17 + 3n
