Question

- The sum of n natural numbers is 5n2 + 4n.
Find its 8th term.

Please solve

Answer 1

Let us assume that the n =8,  

=320+32

=352

refers the sum of the first 8 numbers of the given sequence, which is equal to the value of 352.

refers the sum of the first 7 numbers of the given sequence, which is equal to the value of 273.

For n =7,  

= 245+28  

= 273.

By subtracting the sum of first 8 numbers by the sum of first 7 numbers to get the value of .

Therefore the term íѕ 273