2. A high-quality window triples the cost of a traditional window (assume $X ). The extra cost of using the high-quality windows is fully loaned from a bank for Q years with an annual interest rate of m (in % ). This results in an annual energy saving of n (in \%) (assume the total annual energy cost is $Y ). Assume the average monthly energy cost growth rate is p (in \%). Please derive the equation to determine the month when the energy saving is over the extra loan payment due to the use of highquality windows. Calculate the number if X=100,000,Y=20,000,m=7%,n=5%,p=0.3%,Q=30