Question

in an AP, 7 times the 7th term is equal to 11 times the 11th term. find the 18th term of the AP

Answer 1

ATQ :

7(a7) = 11(a11)
=> 7 (a + 6d) = 11 ( a + 10d)
=> 7a + 42d = 11a +110d
=> -4a = 68d
=> a = -17d
=> -a = 17d -----------(1)

a18 = a + 17d ( from 1)
=> a18 = a + (-a)
=> a18 = 0

Answer 2

THERE IS THE SOLUTION



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