Question

If the seven time the 7th term of AP is equal to eleven time the 11th term then what is the 18th term will be :​

Answer 1

Answer:

The value of $a_{18}$ is 0.

Step-by-step explanation:

According to the question,

$7a_7=11a_{11}$

We have to find $a_{18}$

Recall that $a_n=a+(n-1)d$

Hence,

$a_7=a+(7-1)d=a+6d\\a_{11}=a+(11-1)d=a+10d$

$a_{18}=a+(18-1)d=a+17d$

Now, according to the question, $7a_7=11a_{11}$

Hence,

$7(a+6d)=11(a+10d)$

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

$4a+68d=0$

$4(a+17d)=0$

$a+17d=0$

$a+(18-1)d=0$     (Recall that $a_{18}=a+(18-1)d$

Hence, $a_{18}=0$

Hope it helps.

Answer 2

Answer:

0

Step-by-step explanation:

hope it helps you all the best