what is the intermediate step in the form (x a)^2=b(x a) 2 =b as a result of completing the square for the following equation?

Margaret is purchasing a house for $210,000 with a 15 year fixed rate mortgage at 4.75% interest she has made a 5% down payment the house is valued at 205,000 and the local tax rate is 3.5% homeowners insurance 600 per year what are her total monthly payment