Yes, that is a compound interest formula that solves for monthly payment. All I'm trying to do is separate the variable to where i is alone on one side of the equation. The original formula solves for Payment (P)
There is also:
n = number of months
A = amount financed
i = monthly interest (APR/12)
The original formula that solves for payment is:
P = A x i
-------
1 - (1 + i) ^ -n
I haven't taken algebra since high school 20 years ago, so I am very rusty. Due to the exponent with n, I cannot reorganize the formula to where it solves for i (monthly interest)