I've tried to rearrange the equation below to give an equation in n, to show me the number of years left at a particular interest rate, monthly repayment and loan amount. I am getting lost around taking the n't root.
The following formula is used to calculate the fixed monthly payment (P) required to fully amortize a loan of L dollars over a term of n months at a monthly interest rate of c. [If the quoted rate is 6%, for example, c is .06/12 or .005].
P = L[c(1 + c)^n]/[(1 + c)^n - 1
Any help appreciated, I'd like to see how you got there, about 15 years ago I was not bad at this sort of thing but have maybe lost it a little.