Question

If 7 times the 7th term of an A.P is equal to 11 times its 11th term, then find its 18th term.
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Answer 1

Answer:

18th term is zero

Step-by-step explanation:

7th term is a+6d

11th term is a+10d

7a+42d=11a+110d

-4a=68d

-a=17d

18th term will be a+17d

and we know 17d=-a;

so 18th term =

a-a=0

so

18th term is zero.

Answer 2

Answer:

refer pic

we have to prove that both are equal