Question

if sum of first n terms of an ap is 199 and the sum of first n+1 terms is 289 then a n+1 =

Answer 1

$a_{n+1}=S_{n+1}-S_n\\\\a_{n+1}=289-199\\\\a_{n+1}=\large\mathbf{90}$

Answer 2

$\huge\bf{Answer:-}$

Refer the attachment.