A variable-rate mortgage of $136,000 is amortized over 20 years by equal monthly payments. After 12 months the original interest rate of 7% compounded semi-annually was raised to 7.5% compounded semb-annually. Two years after the mortgage was taken out, if was renewed at the request of the mortgagor at a fored rate of 7.1% compounded semi-annualiy for a four-year term. (a) Calculate the mortgage balance after 12 months. (b) Compute the size of the new monthly payment at the 7.5% rate of interest. (c) Determine the mortgage balance at the end of the four-year term. (a) The mortgage balance is $ after 12 months; (Round the final answer to the nearest cent as needed. Round all intermediate values to six decimal places as needed.) (b) The size of the new monthly payerent is $ (Round the final answer to the nearest cent as needed. Round al intermediase valuos to six decimal places as needed) (c) The mortgage balance is 5 (Round the final answer to the nearest cent as needed. Round all intermediate values to six decimal places as needed.)