Question

the 8th term of an ap is zero prove that its 38 term is triple of its 18 term

Answer 1

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Answer 2

a8 = 0 
a + 7 d = 0
a = - 7d 

a38 = 3 a18 
a + 37d = 3 ( a + 17d ) 
-7d + 37 d = -21d + 51d 

30d = 30d  

 hence proved