Lillian purchased a violin from Smash Music Stores. It regularly sold for $670, but was on sale at 10% off. She also had to pay 8% sales tax. She bought it on an installment plan and paid 15% of the total cost with tax as a down payment. Her monthly payments were$58 per month for 1 year. If Lillian models her payment plan as an arithmetic sequence, give the first term 1 a 1 ​ and the common ratio d.