Question

If the 7 times the 7th term of an ap is equals to 11 times its 11th term then find its 18th term

Answer 1

Answer:

0

Step-by-step explanation:

$7*T_{7} =11*T_{11};\\7(a+(7-1)d)=11(a+(11-1)d)\\7a+42d=11a+110d;\\42d-110d=11a-7a;\\-68d=4a;\\a=-17d;\\\\\\T_{18}=a+(18-1)d =-17d+17d =0$