Anyone? willing to help with them 3.

Abbey purchased a house using a fixed rate mortgage. the annual interest rate is 4.2% compounded monthly for 20 years. the mortgage amount is $235,000. what is the monthly payment on the mortgage? this isn't a multiple choice question have to show my work

What is best way to getting answer for my exam is

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36