Find the answer and EXPLAIN how you got it.

3. The partial sum in the arithmetic series with first term 17 and a common difference 3 is 30705. How many terms are in the series? 4. An arithmetic sequence aj, a2, . .., a100 has a sum of 15,000. Find the first term and the common difference if the sum of the terms in the sequence a3, a6, a9, . . . , agg is 5016. 5. The sum of an infinite geometric series is 108, while the sum of the first, 3 terms is 112. Determine the first term of this series. bus 0= b 2k+1 _2k-1 6. Evaluate the infinite series 32 _ 20 33-21 + + + + . .. 51 07 52 5k 19 7. Let n = 0.123 = 0.123123... be a nonterminating repeating decimal. Find a rational number that is equal to n by expressing n as an infinite geometric series. Simplify your