How many terms of the sequence 
should be taken so that their sum is zero?
Sn = 
[2a + (n – 1) d]
0 = 
[2(18) + (n – 1) (-2)]
38n – 2n2 = 0
n = 0 (which is not possible)
n = 19
Therefore, n = 19 terms
5
How many terms of the sequence should be taken so that their sum is zero?
Sn = [2a + (n – 1) d]
0 = [2(18) + (n – 1) (-2)]
38n – 2n2 = 0
n = 0 (which is not possible)
n = 19
Therefore, n = 19 terms