Arithmetic Sequences: Given,923,908,993,978,.... a) Write a recursive description, and use it to find the 10th term. b) Write an explicit description, and use it to find the 80th term. c) Find the sum of the first 80 terms. Geometric Sequences: Given, 1000, 900,810,729,.... a) Write a recursive description, and use it to find the 6th term. b) Write an explicit description, and use it to find the 25th term. c) Find the sum of the first 25 terms