Here is an example I did of the problem hope it helps let me know if you need anything else~!
~<span>Cecildoesscience </span>
Use the formula of the future value of annuity ordinary and solve for pmt
First deducted the amount of down payment
184,500−184,500×0.20=147,600
Pmt=147,600÷(((1+0.085
÷12)^(12×10)−1)÷(0.085÷12))
=784.53 per month
Im pretty sure its 18 unless im reading it wrong
(x^2-1)(x^2+7) should be your answer