If 7 times the 7th term of an AP is equal to 11times the 11th term,then find the 18th term?

If 7 times the 7th term of an AP is equal to 11times the 11th term,the

1.	If 7 times the 7th term of an AP is equal to 11times the 11th term,then find the 18th term?
Answer» Let 1st term of AP be \'a\',Let the common difference be \'d\',So,as per question, 7 x 7th term = 11 x 11th termor, 7 [a+6d] = 11 [a+10d]or, 7a+42d = 11a +110dor, 4a + 68d = 0or, a + 17d = 0 .......(1)Now, 18th term = a+17dor, t18\xa0= 0 (from 1)