If the first term of an ap is 17 or 350 respectively and the common difference is 9 .find the sum

If the first term of an ap is 17 or 350 respectively and the common di

1.	If the first term of an ap is 17 or 350 respectively and the common difference is 9 .find the sum
Answer» an= a+( n -1)d350=17+(n - 1)×9350-17=( n-1)×9333=(n-1)×9333÷9=(n-1)37=( n-1)n=37+1n=38Sn=n/2(a+l)Sn=38÷2(17+350)Sn=19×367Sn=6973