Respuesta :

difference between each term :_

9 15 21 27 33
second difference:-
6 6 6 6
Dividing this by 2  = 3
so first part of nth term is 3n^2
Substituting n into 3n^2 :-
= 3  12  27  48 75
Now take these values from the original numbers:-
-4 -4 -4 -4 -4 

So the required nth term is 3n^2 - 4

Otras preguntas