Do 23,24,26,27 and use which ever formula goes with it here is the formulas: a n = a ? r to the power of n-1 or Sn= a(1-r^n) if r don't equal 1 or 1-r if r=1

In Exercises 23-28, determine which of the sequences are geo- metric progressions. For each geometric progression, find the seventh term and the sum of the first seven terms. 1 23. 4, 8, 16, 32, . .. 24. 1, 2' 4' 3 1 9manin's 25. 26. 0.004, 0.04, 0.4, 4, ... 8' 4' 64' . . . 27. 243, 81, 27, 9, .. . 28. -1, 1, 3, 5