Problems 17 -20, write out each sum. 17. ( 2k + 3 ) 18. M 2 19. 1 20. 2k+1 (-1) * In k K= 0 K = 2 Problems 21 - 24, write each sum using summation notation. 21. 1+ 3 + 5 + 7+ ...+ [2(15) - 1] 22. 1 - 3+2 -2+...+ (-1)8 (28) 23. 13 + 23 + 33+... + 93 24. 0+ + + + ... + on Problems 25 - 28, find the sum of each sequence. 25. 30 26. k 27. 18, 28. 20 ( k2 + 3 ) (5k + 3) 3 Problems 29-30, solve. 29. Max bought a car by taking per month. His normal