can someone answer all parts please

Muhammad has a mortgage for $346,049.00. The term of the mortgage is 3 years, and the amortization period is 15 years. Muhammad will make weekly payments and the mortgage rate is r2) = 6.500%. The bank offers Muhammad a flexible repayment plan, so once a year he can miss a payment or make a payment twice as large as usual. Each year, Muhammad misses the first payment of the year. a) How much would Muhammad owe at the end of the mortgage term if they didn't miss any payments? b) How much does Muhammad still owe at the end of the mortgage term (including the extra/missed payments)? $