Using a spreadsheet program, construct a 30-year mortgage calculator and determine how long it takes to pay off the loan if a certain additional amount is paid towards principal each month. For reference purposes, assume the principal is $500,000.00, the annual interest rate of the loan is 7% and the additional principal payment is $1000.00. Submit a document stating: 1. The purpose of the document 2. The spreadsheet information, or appropriate snapshots, and graphs as pertinent. 3. Conclusions and observations