Jonathan has a 5-year car loan with a monthly payment of $350. The interest rate on his loan is 4.25%. If he made an initial down payment of $1,500, what was the amount he paid for his car? Jonathan has decided that he would like to pay off his loan early. If he pays an additional $50 per month, how much sooner can he repay his loan? What if he pays $100 extra instead of $50?

Could somebody help me sovle this without using excel spreadsheet? Thanks