c. Answer what is asked. 1. Find the sum of the first 13 terms of the sequence : -3,-1, 1, 3 2. Find the sum of the first 15 terms of the arithmetic sequence: 10, 15, 20,25, ... ? 3. Find the sum of the first 11 terms of the arithmetic sequence : -4,3,10,17,...? 4. Find the sum of the first 19 terms of the arithmetic sequence:
