Question

very fast pls solve this question

Answer 1

16)-

7×(a+6d)=11×(a+10d),

7a+42d=11a+110d,

then

0=11a-7a+110d-42d,

4a+68d=0,

then it becomes

a+17d=0=18th term,

therefore 18th term of this A.P will be zero