Question

What is the nth term of the quadratic sequence 7 , 14 , 23 , 34 , 47 , 62 , 79?

Answer 1

are you asking for the 9th term or the 10th term?

Answer 2

First difference in the sequence is:-

7  9  11  13  15  17

second difference =  2 so nth term contains n2

subtracting  n^2 from the sequence

7    14    23   34    47

1      4     9    16     25    

=  6   10  14  18 22  this is an AP with first term 6 and common diff = 4

so formula is    n^2 + ( 6 + 4(n - 1)

= n^2 + 4n + 2  answer