HELP ME SOLVE PROBLEM $5$ ONLY AND GIVE ME THE ANSWER IN EXCEL FORMULAS. YOU HAVE TO GET YEAR $1=6\mathrm{.}6\%$ I WILL MARK IT WRONG IF YOU DONT

Five years ago, you purchase a house of $$500,000.$ You borrow a mortgage with $80\%$ of LTV $($loan to value ratio$).$ The interest rate on the mortgage is $5\%.$ Payment terms are being made monthly to amortize the loan over $30$ years. You have found another lender who will refinance the current outstanding loan balance at $4\mathrm{.}0\%$ with monthly payments for $30$ years. The new lender will charge two discount points on the new loan. Other refinancing costs will equal $$2,000.$

$1.$ What is your monthly payment for the current loan?

N$(360)$ I $(5/12)$ PV$(400000)$ PMT$(?=-2147\mathrm{.}29)$ FV$(0)$

$2.$ What is the new loan amount if you choose to refinance?

$$367,314\mathrm{.}93$

$3.$ What is your monthly payment for the new loan?

$$1753\mathrm{.}62$

$4.$ What is the effective cost of your new loan if you hold the loan for $30$ years?

$4\mathrm{.}21\%$

$5.$ If you want to refinance today, at least how many years should you stay in the house $($do not prepay$)?$ At least $3$ years.