Question

which term of the AP 21 18 15 is zero

Answer 1

7 th term
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Answer 2

AP: 21 , 18 , 15...
a=21. d=-3
nth term= a+ (n-1)d
0 = 21 + (n-1) (-3)
-21/-3 = n-1
7+1 = n =8
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