Daniel and Jan agreed to pay $ $561,000$ for a four$-$bedroom colonial home in Waltham, Massachusetts, with a $ $70,000$ down payment. They have a $25-$year montgage at a fixed rate of $63/8\%.($Use Table $151.)$ a$.$ How much is their monthly payment? Note: Do not round intermediate calculations. Round your answer to the nearest cent. b$.$ After the first payment, what would be the balance of the principal? Note: Do not round intermediate calculations. Round your answers to the nearest cent.Amortization table $($mortgage principal and interest per $ $1,000)$