[填空题]
In an arithmetic sequence, 65ek))syax gqo gwqv 45z m.n8the sum of the 2 nd and 6 th term is 3:i9zkzzv0 n*.z2g uaam6 hyi ;s m,5xj2 .
Given that the sum of the first six terms is 120 , determine the first term and common difference of the sequence.An arithmetic sequence has first term 45 and common difference -1.5 .
1. Given that the k th term of the sequence is zero, find the value of k .
Let $S_{n}$ denote the sum of the first n terms of the sequence.
2. Find the maximum value of $S_{n}$ .
