Answer:
$563.24
Explanation:
The monthly payment on a mortgage loan is found using the amortization formula:
A = P(r/12)/(1 -(1 +r/12)^(-12t))
where A is the monthly payment on a loan of P at interest rate r for t years.
Filling in the given values, we find the payment to be ...
A = $70,000×(0.09/12)/(1 -(1 +0.09/12)^(-12·30)) ≈ $563.236
The monthly payment is about $563.24.
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Additional comment
Many graphing calculators and all spreadsheets have functions that will do this calculation for you.