pls help

Rewrite using sigma notation: 9. 748+9+10+11 2+4+8+16 11. -10 + 20-30 + 40 For each sequence, state if it is arithmetic, geometric, or neither. If it is arithmetic, tell the common difference. If it is geometric, tell the common ratio. Then, find the sum of the first 50 terms (if possible). 12. 1, 10, 19, 28, 37, .... 13. 4, 4.4, 4.84, 5.324, 5.8564,.. S50 = S50 = 14. 2, 1, 1/2, 4/4, ... 15. 7, 1, 9, 3, 11, 5, ... S50 = Evaluate. 17. 8C1 18. 363 16. 7C5 Find each term described. 19.) 3'd term in expansion of (x + 8)5 20) 2nd term in expansion of (3x - 5y)3 Expand completely. 21) (4x - y ) 4